How do I make the first letter of a string uppercase in JavaScript?

Question

How do I make the first character of a string uppercase if it's a letter, but not change the case of any of the other letters?

For example:

• "this is a test" → "This is a test"
• "the Eiffel Tower" → "The Eiffel Tower"
• "/index.html" → "/index.html"

Answer 1

function capitalizeFirstLetter(string) {
    return string.charAt(0).toUpperCase() + string.slice(1);
}

Some other answers modify String.prototype (this answer used to as well), but I would advise against this now due to maintainability (hard to find out where the function is being added to the prototype and could cause conflicts if other code uses the same name/a browser adds a native function with that same name in future).

Answer 2

Edited to add this DISCLAIMER: please read the comments to understand the risks of editing JS basic types.

---

Here's a more object-oriented approach:

Object.defineProperty(String.prototype, 'capitalize', {
  value: function() {
    return this.charAt(0).toUpperCase() + this.slice(1);
  },
  enumerable: false
});

You'd call the function, like this:

"hello, world!".capitalize();

With the expected output being:

"Hello, world!"

Answer 3

In CSS:

p::first-letter {
    text-transform:capitalize;
}

Answer 4

Here is a shortened version of the popular answer that gets the first letter by treating the string as an array:

function capitalize(s)
{
    return s[0].toUpperCase() + s.slice(1);
}

Update

According to the comments below this doesn't work in IE 7 or below.

Update 2:

To avoid undefined for empty strings (see @njzk2's comment below), you can check for an empty string:

function capitalize(s)
{
    return s && s[0].toUpperCase() + s.slice(1);
}

ES6 version

const capitalize = s => s && s[0].toUpperCase() + s.slice(1)

// to always return type string event when s may be falsy other than empty-string
const capitalize = s => (s && s[0].toUpperCase() + s.slice(1)) || ""

Answer 5

If you're interested in the performance of a few different methods posted:

Here are the fastest methods based on this jsperf test (ordered from fastest to slowest).

As you can see, the first two methods are essentially comparable in terms of performance, whereas altering the String.prototype is by far the slowest in terms of performance.

// 10,889,187 operations/sec
function capitalizeFirstLetter(string) {
    return string[0].toUpperCase() + string.slice(1);
}

// 10,875,535 operations/sec
function capitalizeFirstLetter(string) {
    return string.charAt(0).toUpperCase() + string.slice(1);
}

// 4,632,536 operations/sec
function capitalizeFirstLetter(string) {
    return string.replace(/^./, string[0].toUpperCase());
}

// 1,977,828 operations/sec
String.prototype.capitalizeFirstLetter = function() {
    return this.charAt(0).toUpperCase() + this.slice(1);
}

Answer 6

I didn’t see any mention in the existing answers of issues related to astral plane code points or internationalization. “Uppercase” doesn’t mean the same thing in every language using a given script.

Initially I didn’t see any answers addressing issues related to astral plane code points. There is one, but it’s a bit buried (like this one will be, I guess!)

Overview of the hidden problem and various approaches to it

Most of the proposed functions look like this:

function capitalizeFirstLetter(str) {
  return str[0].toUpperCase() + str.slice(1);
}

However, some cased characters fall outside the BMP (basic multilingual plane, code points U+0 to U+FFFF). For example take this Deseret text:

capitalizeFirstLetter(""); // ""

The first character here fails to capitalize because the array-indexed properties of strings don’t access “characters” or code points*. They access UTF-16 code units. This is true also when slicing — the index values point at code units.

It happens to be that UTF-16 code units are 1:1 with USV code points within two ranges, U+0 to U+D7FF and U+E000 to U+FFFF inclusive. Most cased characters fall into those two ranges, but not all of them.

From ES2015 on, dealing with this became a bit easier. String.prototype[@@iterator] yields strings corresponding to code points**. So for example, we can do this:

function capitalizeFirstLetter([ first='', ...rest ]) {
  return [ first.toUpperCase(), ...rest ].join('');
}

capitalizeFirstLetter("") // ""

For longer strings, this is probably not terribly efficient*** — we don’t really need to iterate the remainder. We could use String.prototype.codePointAt to get at that first (possible) letter, but we’d still need to determine where the slice should begin. One way to avoid iterating the remainder would be to test whether the first codepoint is outside the BMP; if it isn’t, the slice begins at 1, and if it is, the slice begins at 2.

function capitalizeFirstLetter(str) {
  if (!str) return '';

  const firstCP = str.codePointAt(0);
  const index = firstCP > 0xFFFF ? 2 : 1;

  return String.fromCodePoint(firstCP).toUpperCase() + str.slice(index);
}

capitalizeFirstLetter("") // ""

You could use bitwise math instead of > 0xFFFF there, but it’s probably easier to understand this way and either would achieve the same thing.

We can also make this work in ES5 and below by taking that logic a bit further if necessary. There are no intrinsic methods in ES5 for working with codepoints, so we have to manually test whether the first code unit is a surrogate****:

function capitalizeFirstLetter(str) {
  if (!str) return '';

  var firstCodeUnit = str[0];

  if (firstCodeUnit < '\uD800' || firstCodeUnit > '\uDFFF') {
    return str[0].toUpperCase() + str.slice(1);
  }

  return str.slice(0, 2).toUpperCase() + str.slice(2);
}

capitalizeFirstLetter("") // ""

Deeper into internationalization (whose capitalization?)

At the start I also mentioned internationalization considerations. Some of these are very difficult to account for because they require knowledge not only of what language is being used, but also may require specific knowledge of the words in the language. For example, the Irish digraph "mb" capitalizes as "mB" at the start of a word. Another example, the German eszett, never begins a word (afaik), but still helps illustrate the problem. The lowercase eszett (“ß”) capitalizes to “SS,” but “SS” could lowercase to either “ß” or “ss” — you require out-of-band knowledge of the German language to know which is correct!

The most famous example of these kinds of issues, probably, is Turkish. In Turkish Latin, the capital form of i is İ, while the lowercase form of I is ı — they’re two different letters. Fortunately we do have a way to account for this:

function capitalizeFirstLetter([ first='', ...rest ], locale) {
  return [ first.toLocaleUpperCase(locale), ...rest ].join('');
}

capitalizeFirstLetter("italy", "en") // "Italy"
capitalizeFirstLetter("italya", "tr") // "İtalya"

In a browser, the user’s most-preferred language tag is indicated by navigator.language, a list in order of preference is found at navigator.languages, and a given DOM element’s language can be obtained (usually) with Object(element.closest('[lang]')).lang || YOUR_DEFAULT_HERE in multilanguage documents.

In agents which support Unicode property character classes in RegExp, which were introduced in ES2018, we can clean stuff up further by directly expressing what characters we’re interested in:

function capitalizeFirstLetter(str, locale=navigator.language) {
  return str.replace(/^\p{CWU}/u, char => char.toLocaleUpperCase(locale));
}

This could be tweaked a bit to also handle capitalizing multiple words in a string with fairly good accuracy for at least some languages, though outlying cases will be hard to avoid completely if doing so no matter what the primary language is.

The CWU or Changes_When_Uppercased character property matches all code points which change when uppercased in the generic case where specific locale data is absent. There are other interesting case-related Unicode character properties that you may wish to play around with. It’s a cool zone to explore but we’d go on all day if we enumerated em all here. Here’s something to get your curiosity going if you’re unfamiliar, though: \p{Lower} is a larger group than \p{LowercaseLetter} (aka \p{Ll}) — conveniently illustrated by the default character set comparison in this tool provided by Unicode. (NB: not everything you can reference there is also available in ES regular expressions, but most of the stuff you’re likely to want is).

Alternatives to case-mapping in JS (Firefox & CSS love the Dutch!)

If digraphs with unique locale/language/orthography capitalization rules happen to have a single-codepoint “composed” representation in Unicode, these might be used to make one’s capitalization expectations explicit even in the absence of locale data. For example, we could prefer the composed i-j digraph, ij / U+133, associated with Dutch, to ensure a case-mapping to uppercase IJ / U+132:

capitalizeFirstLetter('ijsselmeer'); // "IJsselmeer"

On the other hand, precomposed digraphs and similar are sometimes deprecated (like that one, it seems!) and may be undesirable in interchanged text regardless due to the potential copypaste nuisance if that’s not the normal way folks type the sequence in practice. Unfortunately, in the absence of the precomposition “hint,” an explicit locale won’t help here (at least as far as I know). If we spell ijsselmeer with an ordinary i + j, capitalizeFirstLetter will produce the wrong result even if we explicitly indicate nl as the locale:

capitalizeFirstLetter('ijsselmeer', 'nl'); // "Ijsselmeer" :(

(I’m not entirely sure whether there are some such cases where the behavior comes down to ICU data availability — perhaps someone else could say.)

If the point of the transformation is to display textual content in a web browser, though, you have an entirely different option available that will likely be your best bet: leveraging features of the web platform’s other core languages, HTML and CSS. Armed with HTML’s lang=... and CSS’s text-transform:..., you’ve got a (pseudo-)declarative solution that leaves extra room for the user agent to be “smart.” A JS API needs to have predictable outcomes across all browsers (generally) and isn’t free to experiment with heuristics. The user-agent itself is obligated only to its user, though, and heuristic solutions are fair game when the output is for a human being. If we tell it “this text is Dutch, but please display it capitalized,” the particular outcome might now vary between browsers, but it’s likely going to be the best each of them could do. Let’s see:

<!DOCTYPE html>
<dl>
<dt>Untransformed
<dd>ijsselmeer
<dt>Capitalized with CSS and <code>lang=en</code>
<dd lang="en" style="text-transform: capitalize">ijsselmeer
<dt>Capitalized with CSS and <code>lang=nl</code>
<dd lang="nl" style="text-transform: capitalize">ijsselmeer

In Chromium at the time of writing, both the English and Dutch lines come out as Ijsselmeer — so it does no better than JS. But try it in current Firefox! The element that we told the browser contains Dutch will be correctly rendered as IJsselmeer there.

This solution is purpose-specific (it’s not gonna help you in Node, anyway) but it was silly of me not to draw attention to it previously given some folks might not realize they’re googling the wrong question. Thanks @paul23 for clarifying more about the nature of the IJ digraph in practice and prompting further investigation!

---

As of January 2021, all major engines have implemented the Unicode property character class feature, but depending on your target support range you may not be able to use it safely yet. The last browser to introduce support was Firefox (78; June 30, 2020). You can check for support of this feature with the Kangax compat table. Babel can be used to compile RegExp literals with property references to equivalent patterns without them, but be aware that the resulting code can sometimes be enormous. You probably would not want to do this unless you’re certain the tradeoff is justified for your use case.

---

In all likelihood, people asking this question will not be concerned with Deseret capitalization or internationalization. But it’s good to be aware of these issues because there’s a good chance you’ll encounter them eventually even if they aren’t concerns presently. They’re not “edge” cases, or rather, they’re not by-definition edge cases — there’s a whole country where most people speak Turkish, anyway, and conflating code units with codepoints is a fairly common source of bugs (especially with regard to emoji). Both strings and language are pretty complicated!

---

* The code units of UTF-16 / UCS2 are also Unicode code points in the sense that e.g. U+D800 is technically a code point, but that’s not what it “means” here ... sort of ... though it gets pretty fuzzy. What the surrogates definitely are not, though, is USVs (Unicode scalar values).

** Though if a surrogate code unit is “orphaned” — i.e., not part of a logical pair — you could still get surrogates here, too.

*** maybe. I haven’t tested it. Unless you have determined capitalization is a meaningful bottleneck, I probably wouldn’t sweat it — choose whatever you believe is most clear and readable.

**** such a function might wish to test both the first and second code units instead of just the first, since it’s possible that the first unit is an orphaned surrogate. For example the input "\uD800x" would capitalize the X as-is, which may or may not be expected.

Answer 7

For another case I need it to capitalize the first letter and lowercase the rest. The following cases made me change this function:

//es5
function capitalize(string) {
    return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
}
capitalize("alfredo")  // => "Alfredo"
capitalize("Alejandro")// => "Alejandro
capitalize("ALBERTO")  // => "Alberto"
capitalize("ArMaNdO")  // => "Armando"

// es6 using destructuring 
const capitalize = ([first,...rest]) => first.toUpperCase() + rest.join('').toLowerCase();

Answer 8

If you're already (or considering) using Lodash, the solution is easy:

_.upperFirst('fred');
// => 'Fred'

_.upperFirst('FRED');
// => 'FRED'

_.capitalize('fred') //=> 'Fred'

See their documentation: https://lodash.com/docs#capitalize

_.camelCase('Foo Bar'); //=> 'fooBar'

https://lodash.com/docs/4.15.0#camelCase

_.lowerFirst('Fred');
// => 'fred'

_.lowerFirst('FRED');
// => 'fRED'

_.snakeCase('Foo Bar');
// => 'foo_bar'

Vanilla JavaScript for first upper case:

function upperCaseFirst(str){
    return str.charAt(0).toUpperCase() + str.substring(1);
}

Answer 9

This is the 2018 ECMAScript 6+ Solution:

const str = 'the Eiffel Tower';
const newStr = `${str[0].toUpperCase()}${str.slice(1)}`;
console.log('Original String:', str); // the Eiffel Tower
console.log('New String:', newStr); // The Eiffel Tower

Answer 10

There is a very simple way to implement it by replace. For ECMAScript 6:

'foo'.replace(/^./, str => str.toUpperCase())

Result:

'Foo'

Answer 11

CSS only

If the transformation is needed only for displaying on a web page:

p::first-letter {
  text-transform: uppercase;
}

• Despite being called "::first-letter", it applies to the first character, i.e. in case of string %a, this selector would apply to % and as such a would not be capitalized.
• In IE9+ or IE5.5+ it's supported in legacy notation with only one colon (:first-letter).

ES2015 one-liner

const capitalizeFirstChar = str => str.charAt(0).toUpperCase() + str.substring(1);

Remarks

• In the benchmark I performed, there was no significant difference between string.charAt(0) and string[0]. Note however, that string[0] would be undefined for an empty string, so the function would have to be rewritten to use "string && string[0]", which is way too verbose, compared to the alternative.
• string.substring(1) is faster than string.slice(1).

Benchmark between substring() and slice()

The difference is rather minuscule nowadays (run the test yourself):

• 21,580,613.15 ops/s ±1.6% for substring(),
• 21,096,394.34 ops/s ±1.8% (2.24% slower) for slice().

Answer 12

Capitalize the first letter of all words in a string:

function ucFirstAllWords( str )
{
    var pieces = str.split(" ");
    for ( var i = 0; i < pieces.length; i++ )
    {
        var j = pieces[i].charAt(0).toUpperCase();
        pieces[i] = j + pieces[i].substr(1);
    }
    return pieces.join(" ");
}

Answer 13

It's always better to handle these kinds of stuff using CSS first, in general, if you can solve something using CSS, go for that first, then try JavaScript to solve your problems, so in this case try using :first-letter in CSS and apply text-transform:capitalize;

So try creating a class for that, so you can use it globally, for example: .first-letter-uppercase and add something like below in your CSS:

.first-letter-uppercase:first-letter {
    text-transform:capitalize;
}

Also the alternative option is JavaScript, so the best gonna be something like this:

function capitalizeTxt(txt) {
  return txt.charAt(0).toUpperCase() + txt.slice(1); //or if you want lowercase the rest txt.slice(1).toLowerCase();
}

and call it like:

capitalizeTxt('this is a test'); // return 'This is a test'
capitalizeTxt('the Eiffel Tower'); // return 'The Eiffel Tower'
capitalizeTxt('/index.html');  // return '/index.html'
capitalizeTxt('alireza');  // return 'Alireza'
capitalizeTxt('dezfoolian');  // return 'Dezfoolian'

If you want to reuse it over and over, it's better attach it to javascript native String, so something like below:

String.prototype.capitalizeTxt = String.prototype.capitalizeTxt || function() {
    return this.charAt(0).toUpperCase() + this.slice(1);
}

and call it as below:

'this is a test'.capitalizeTxt(); // return 'This is a test'
'the Eiffel Tower'.capitalizeTxt(); // return 'The Eiffel Tower'
'/index.html'.capitalizeTxt();  // return '/index.html'
'alireza'.capitalizeTxt();  // return 'Alireza'

Answer 14

String.prototype.capitalize = function(allWords) {
   return (allWords) ? // If all words
      this.split(' ').map(word => word.capitalize()).join(' ') : // Break down the phrase to words and then recursive
                                                                 // calls until capitalizing all words
      this.charAt(0).toUpperCase() + this.slice(1); // If allWords is undefined, capitalize only the first word,
                                                    // meaning the first character of the whole string
}

And then:

 "capitalize just the first word".capitalize(); ==> "Capitalize just the first word"
 "capitalize all words".capitalize(true); ==> "Capitalize All Words"

Update November 2016 (ES6), just for fun:

const capitalize = (string = '') => [...string].map(    // Convert to array with each item is a char of
                                                        // string by using spread operator (...)
    (char, index) => index ? char : char.toUpperCase()  // Index true means not equal 0, so (!index) is
                                                        // the first character which is capitalized by
                                                        // the `toUpperCase()` method
 ).join('')                                             // Return back to string

then capitalize("hello") // Hello

Answer 15

SHORTEST 3 solutions, 1 and 2 handle cases when s string is "", null and undefined:

 s&&s[0].toUpperCase()+s.slice(1)        // 32 char

 s&&s.replace(/./,s[0].toUpperCase())    // 36 char - using regexp

'foo'.replace(/./,x=>x.toUpperCase())    // 31 char - direct on string, ES6

let s='foo bar';

console.log( s&&s[0].toUpperCase()+s.slice(1) );

console.log( s&&s.replace(/./,s[0].toUpperCase()) );

console.log( 'foo bar'.replace(/./,x=>x.toUpperCase()) );

Answer 16

Here is a function called ucfirst()(short for "upper case first letter"):

function ucfirst(str) {
    var firstLetter = str.substr(0, 1);
    return firstLetter.toUpperCase() + str.substr(1);
}

You can capitalise a string by calling ucfirst("some string") -- for example,

ucfirst("this is a test") --> "This is a test"

It works by splitting the string into two pieces. On the first line it pulls out firstLetter and then on the second line it capitalises firstLetter by calling firstLetter.toUpperCase() and joins it with the rest of the string, which is found by calling str.substr(1).

You might think this would fail for an empty string, and indeed in a language like C you would have to cater for this. However in JavaScript, when you take a substring of an empty string, you just get an empty string back.

Answer 17

We could get the first character with one of my favorite RegExp, looks like a cute smiley: /^./

String.prototype.capitalize = function () {
  return this.replace(/^./, function (match) {
    return match.toUpperCase();
  });
};

And for all coffee-junkies:

String::capitalize = ->
  @replace /^./, (match) ->
    match.toUpperCase()

...and for all guys who think that there's a better way of doing this, without extending native prototypes:

var capitalize = function (input) {
  return input.replace(/^./, function (match) {
    return match.toUpperCase();
  });
};

Answer 18

Use:

var str = "ruby java";

console.log(str.charAt(0).toUpperCase() + str.substring(1));

It will output "Ruby java" to the console.

Answer 19

If you use Underscore.js or Lodash, the underscore.string library provides string extensions, including capitalize:

_.capitalize(string) Converts first letter of the string to uppercase.

Example:

_.capitalize("foo bar") == "Foo bar"

Answer 20

If you're ok with capitalizing the first letter of every word, and your usecase is in HTML, you can use the following CSS:

<style type="text/css">
    p.capitalize {text-transform:capitalize;}
</style>
<p class="capitalize">This is some text.</p>

This is from CSS text-transform Property (at W3Schools).

Answer 21

var capitalized = yourstring[0].toUpperCase() + yourstring.substr(1);

Answer 22

If you are wanting to reformat all-caps text, you might want to modify the other examples as such:

function capitalize (text) {
    return text.charAt(0).toUpperCase() + text.slice(1).toLowerCase();
}

This will ensure that the following text is changed:

TEST => Test
This Is A TeST => This is a test

Answer 23

String.prototype.capitalize = function(){
    return this.replace(/(^|\s)([a-z])/g, 
                        function(m, p1, p2) {
                            return p1 + p2.toUpperCase();
                        });
};

Usage:

capitalizedString = someString.capitalize();

This is a text string => This Is A Text String

Answer 24

function capitalize(s) {
    // returns the first letter capitalized + the string from index 1 and out aka. the rest of the string
    return s[0].toUpperCase() + s.substr(1);
}


// examples
capitalize('this is a test');
=> 'This is a test'

capitalize('the Eiffel Tower');
=> 'The Eiffel Tower'

capitalize('/index.html');
=> '/index.html'

Answer 25

yourString.replace(/\w/, c => c.toUpperCase())

I found this arrow function easiest. Replace matches the first letter character (\w) of your string and converts it to uppercase. Nothing fancier is necessary.

Answer 26

A Solution That Works For All Unicode Characters

57 81 different answers for this question, some off-topic, and yet none of them raise the important issue that none of the solutions listed will work with Asian characters, emoji's, and other high Unicode-point-value characters in many browsers. Here is a solution that will:

const consistantCapitalizeFirstLetter = "\uD852\uDF62".length === 1 ?
    function(S) {
        "use-strict"; // Hooray! The browser uses UTF-32!
        return S.charAt(0).toUpperCase() + S.substring(1);
    } : function(S) {
        "use-strict";
        // The browser is using UCS16 to store UTF-16
        var code = S.charCodeAt(0)|0;
        return (
          code >= 0xD800 && code <= 0xDBFF ? // Detect surrogate pair
            S.slice(0,2).toUpperCase() + S.substring(2) :
            S.charAt(0).toUpperCase() + S.substring(1)
        );
    };
const prettyCapitalizeFirstLetter = "\uD852\uDF62".length === 1 ?
    function(S) {
        "use-strict"; // Hooray! The browser uses UTF-32!
        return S.charAt(0).toLocaleUpperCase() + S.substring(1);
    } : function(S) {
        "use-strict";
        // The browser is using UCS16 to store UTF-16
        var code = S.charCodeAt(0)|0;
        return (
          code >= 0xD800 && code <= 0xDBFF ? // Detect surrogate pair
            S.slice(0,2).toLocaleUpperCase() + S.substring(2) :
            S.charAt(0).toLocaleUpperCase() + S.substring(1)
        );
    };

Do note that the above solution tries to account for UTF-32. However, the specification officially states that browsers are required to do everything in UTF-16 mapped into UCS2. Nevertheless, if we all come together, do our part, and start preparing for UTF32, then there is a chance that the TC39 may allow browsers to start using UTF-32 (like how Python uses 24-bits for each character of the string). This must seem silly to an English speaker: no one who uses only latin-1 has ever had to deal with Mojibake because Latin-I is supported by all character encodings. But, users in other countries (such as China, Japan, Indonesia, etc.) are not so fortunate. They constantly struggle with encoding problems not just from the webpage, but also from the JavaScript: many Chinese/Japanese characters are treated as two letters by JavaScript and thus may be broken apart in the middle, resulting in � and � (two question-marks that make no sense to the end user). If we could start getting ready for UTF-32, then the TC39 might just allow browsers do what Python did many years ago which had made Python very popular for working with high Unicode characters: using UTF-32.

consistantCapitalizeFirstLetter works correctly in Internet Explorer 3+ (when the const is changed to var). prettyCapitalizeFirstLetter requires Internet Explorer 5.5+ (see the top of page 250 of this document). However, these fact are more of just jokes because it is very likely that the rest of the code on your webpage will not even work in Internet Explorer 8 - because of all the DOM and JScript bugs and lack of features in these older browsers. Further, no one uses Internet Explorer 3 or Internet Explorer 5.5 any more.

Answer 27

var str = "test string";
str = str.substring(0,1).toUpperCase() + str.substring(1);

Answer 28

yourString.replace(/^[a-z]/, function(m){ return m.toUpperCase() });

EDIT: Regexp is overkill for this, prefer the simpler : str.charAt(0).toUpperCase() + str.substring(1)

Answer 29

Check out this solution:

var stringVal = 'master';
stringVal.replace(/^./, stringVal[0].toUpperCase()); // Returns Master

Answer 30

There are already so many good answers, but you can also use a simple CSS transform:

text-transform: capitalize;

div.text-capitalize {
  text-transform: capitalize;
}

<h2>text-transform: capitalize:</h2>
<div class="text-capitalize">Lorem ipsum dolor sit amet, consectetur adipiscing elit.</div>

Answer 31

Only because this is really a one-liner I will include this answer. It's an ES6-based interpolated string one-liner.

let setStringName = 'the Eiffel Tower';
setStringName = `${setStringName[0].toUpperCase()}${setStringName.substring(1)}`;

Answer 32

with arrow function

let fLCapital = s => s.replace(/./, c => c.toUpperCase())
fLCapital('this is a test') // "This is a test"

with arrow function, another solution

let fLCapital = s => s = s.charAt(0).toUpperCase() + s.slice(1);
fLCapital('this is a test') // "This is a test"

with array and map()

let namesCapital = names => names.map(name => name.replace(/./, c => c.toUpperCase()))
namesCapital(['james', 'robert', 'mary']) // ["James", "Robert", "Mary"]

Answer 33

Here's my version. I think it's easy to understand and elegant too.

var str = "foo bar baz";

// Capitalize
str.split(' ')
    .map(w => w[0].toUpperCase() + w.substr(1).toLowerCase())
    .join(' ')
// Returns "Foo Bar Baz"

// Capitalize the first letter
str.charAt(0).toUpperCase() + str.slice(1)
// Returns "Foo bar baz"

Answer 34

The ucfirst function works if you do it like this.

function ucfirst(str) {
    var firstLetter = str.slice(0,1);
    return firstLetter.toUpperCase() + str.substring(1);
}

Thanks J-P for the aclaration.

Answer 35

You can do it in one line like this

string[0].toUpperCase() + string.substring(1)

Answer 36

A functional approach

const capitalize = ([s, ...tring]) =>
  [s.toUpperCase(), ...tring]
    .join('');

Then you could

const titleCase = str => 
  str
    .split(' ')
    .map(capitalize)
    .join(' ')

Answer 37

The first character of every string is capitalized.

function capitalize(word){
    return word[0].toUpperCase() + word.slice(1).toLowerCase();
}

console.log(capitalize("john")); //John
console.log(capitalize("BRAVO")); //Bravo
console.log(capitalize("BLAne")); //Blane

Answer 38

In CoffeeScript, add to the prototype for a string:

String::capitalize = ->
  @substr(0, 1).toUpperCase() + @substr(1)

Usage would be:

"woobie".capitalize()

Which yields:

"Woobie"

Answer 39

Posting an edit of @salim's answer to include locale letter transformation.

var str = "test string";
str = str.substring(0,1).toLocaleUpperCase() + str.substring(1);

Answer 40

CoffeeScript

ucfirst = (str) -> str.charAt(0).toUpperCase() + str.slice(1)

As a String prototype method:

String::capitalize = -> @charAt(0).toUpperCase() + @slice(1)

Answer 41

function capitalize(string) {
    return string.replace(/^./, Function.call.bind("".toUpperCase));
}

Answer 42

Using the JS replace string method & a regular expression w/ a word boundary seems simple.

Capitalize the first words' first character: "the eiffel tower" --> "The eiffel tower"

str.replace(/\b\w/, v => v.toUpperCase())

Capitalize all words' first character: "the eiffel tower" --> "The Eiffel Tower"

str.replace(/\b\w/g, v => v.toUpperCase())

Answer 43

// Uppercase first letter
function ucfirst(field) {
    field.value = field.value.substr(0, 1).toUpperCase() + field.value.substr(1);
}

Usage:

<input type="text" onKeyup="ucfirst(this)" />

Answer 44

Here are a few suggestions to make a universal function that can capitalize only the first letter, or the first letter of each word, including words separated by a dash or other separators (like some first names in French).

By default, the function capitalizes only the first letter of the whole string, and leave the rest untouched.

Parameters:

• lc: true to force lower-casing the rest of the word(s)
• all: true to capitalize each word

1. No regex version

function capitalize( str, lc, all ) {
    if( all ) {
        return str.split( " " )
            .map( word => capitalize( word, lc ) )
            .join( " " )
            .split( "-" )
            .map( word => capitalize( word, false ) )
            .join( "-" );
    } else {
        return lc
            ? str.charAt( 0 ).toUpperCase() + str.slice( 1 ).toLowerCase()
            : str.charAt( 0 ).toUpperCase() + str.slice( 1 );
    }
}

2. Using regex

function capitalize( str, lc, all ) {
    const replacer = ( m, p1, p2 ) =>
        p1.toUpperCase() + ( lc ? p2.toLowerCase() : p2 );
    if( all ) {
        return str.split( /(\s|-|')/ )
                  .map( s => s.replace( /^([a-z])(.*)$/, replacer ) )
                  .join( "" )
    } else {
        return str.replace( /^([a-z])(.*)$/, replacer )
    }
}

3. Alternative with rest parameters

function capitalizeWord( [first, ...rest], lc ) {
    return first.toUpperCase() + ( lc ? rest.join("").toLowerCase() : rest.join("") );
}
function capitalize( str, lc, all ) {
    return all ? str.split( /(\s|-|')/ )
                    .map( s => capitalizeWord( s, lc ) )
                    .join( "" )
               : capitalizeWord( str, lc );
}

Examples

capitalize( "saiNT-jEAn d'anGÉly", false, false )
// returns "SaiNT-jEAn d'anGÉly"

capitalize( "saiNT-jEAn d'anGÉly", false, true )
// returns "SaiNT-JEAn D'AnGÉly"

capitalize( "saiNT-jEAn d'anGÉly", true, false )
// returns "Saint-jean d'angély"

capitalize( "saiNT-jEAn d'anGÉly", true, true )
// returns "Saint-Jean D'Angély"

Answer 45

Capitalize and Uncapitalize first Char of a String.

Functions to include:

/** First Character uppercase */
function capitalize(str) {
    return str.charAt(0).toUpperCase() + str.slice(1);
}

/** First Character lowercase */
function uncapitalize(str) {
    return str.charAt(0).toLowerCase() + str.slice(1);
}

Example1 "First Character uppercase":

alert(capitalize("hello world"));

Result: Hello world

Example 2 "First Character lowercase":

alert(uncapitalize("Hello World, today is sunny"));

Result: hello World, today is sunny

Answer 46

One possible solution:

function ConvertFirstCharacterToUpperCase(text) {
    return text.substr(0, 1).toUpperCase() + text.substr(1);    
}

Use this:

 alert(ConvertFirstCharacterToUpperCase("this is string"));

Here is working JS Fiddle

Answer 47

Or you could use Sugar.js capitalize()

Example:

'hello'.capitalize()           -> 'Hello'
'hello kitty'.capitalize()     -> 'Hello kitty'
'hello kitty'.capitalize(true) -> 'Hello Kitty'

Answer 48

This solution might be new and probably the simplest.

function firstUpperCase(input)
{
    return input[0].toUpperCase() + input.substr(1);
}

console.log(firstUpperCase("capitalize first letter"));

Answer 49

s[0].toUpperCase``+s.substr`1`

let s = 'hello there'

console.log( s[0].toUpperCase``+s.substr`1` )

Answer 50

If you go with one of the regex answers, remember they will only work with ASCII characters. All your unicode letters will not be uppercased. The XRegExp library and its unicode plugins solve this problem if you want to stick with regexps. So something like this would work:

String.prototype.capitalize = function () {
    return this.replace(XRegExp("^\\p{L}"), function ($0) { return $0.toUpperCase(); })
}

Considering that it still doesn't cover all possibilities (combined characters, see http://www.regular-expressions.info/unicode.html) it seems easier to just use the .charAt(0).toUpperCase() approach.

Answer 51

/*
 * As terse as possible, assuming you're using ES version 6+
 */
var upLetter1=s=>s.replace(/./,m=>m.toUpperCase());

console.log(upLetter1("the quick brown fox jumped over the lazy dog."));
//\\ The quick brown fox jumped over the lazy dog. //\\

Answer 52

Using prototypes

String.prototype.capitalize = function () {
    return this.charAt(0) + this.slice(1).toLowerCase();
  }

or Using functions

function capitalize(str) {
return str.charAt(0).toUpperCase() + str.slice(1).toLowerCase();
}

Answer 53

There are multiple ways of doing this try some below

var lower = 'the Eiffel Tower';
var upper = lower.charAt(0).toUpperCase() + lower.substr(1);

And if you are comfortable with regular expressions, you do things this way:

var upper = lower.replace(/^\w/, function (chr) {
  return chr.toUpperCase();
});

And you can even take it one step further by using more modern syntax:

const upper = lower.replace(/^\w/, c => c.toUpperCase());

Also this will take care of negative scenarios as mentioned in example like words starting with special characters like !@#$%^&*()}{{[];':",.<>/? .

Answer 54

Unicode and Locale Aware

Using current language features:

function capitalize([firstLetter, ...rest]) {
  return [firstLetter.toLocaleUpperCase(), ...rest].join('');
}

console.log(capitalize('foo bar'));
console.log(capitalize('ѷҥӕ'))
console.log(capitalize('❄⭐'));

// Title Case
console.log(
  'Title Case:',
  'foo bar'
    .split(/\s+/)
    .map(capitalize)
    .join(' '),
);

We accept a destructured string as the only parameter [firstLetter, ...rest], assigning the first character to the variable firstLetter and get an array for the rest of the characters (...rest) bound to the rest variable. E.g. for the string lorem ipsum this should look like:

capitalize('lorem ipsum');
// firstLetter = 'l'
// rest = ['o', 'r', 'e', 'm', ' ', 'i', 'p', 's', 'u', 'm'];

Now all we need to do is prepend an uppercased version of the first letter firstLetter.toLocaleUpperCase() to the rest array—using the spread operator—and join the resulting array into a string using .join('')

Answer 55

Using an arrow function:

const capitalize = string => string[0].toUpperCase() + string.slice(1)

Answer 56

Elegant

const capitalize = ([firstChar, ...rest]) => `${firstChar.toUpperCase()}${rest.join('')}`;

Answer 57

This code will also handle extra spaces at the start & end of the string.

let val = '  this is test ';
val = val.trim();
val = val.charAt(0).toUpperCase() + val.slice(1);
console.log("Value => ", val);

Answer 58

You can use regex approach :

str.replace(/(^|\s)\S/g, letter => letter.toUpperCase());

Answer 59

var capitalizeMe = "string not starting with capital"

Capitalize with substr

var capitalized = capitalizeMe.substr(0, 1).toUpperCase() + capitalizeMe.substr(1);

Answer 60

For just capitalizing the first letter and make the rest of the string lower case:

function capitalize(str) {
     var splittedEnter = str.split(" ");
     var capitalized;
     var capitalizedResult;
     for (var i = 0 ; i < splittedEnter.length ; i++){
         capitalized = splittedEnter[i].charAt(0).toUpperCase();
         splittedEnter[i] = capitalized + splittedEnter[i].substr(1).toLowerCase();
    }
    return splittedEnter.join(" ");
}

capitalize("tHiS wiLL be alL CapiTaLiZED.");

The result will be:

This Will Be All Capitalized.

Answer 61

I would just use a regular expression:

myString = '    the quick green alligator...';
myString.trim().replace(/^\w/, (c) => c.toUpperCase());

Answer 62

Just install and load Lodash:

import { capitalize } from "lodash";

capitalize('test') // Test

Answer 63

Simple ES6 syntax with template string

 const capitalize = (str) => {
   return `${str[0].toUpperCase()}${str.slice(1)}`
   // return str[0].toUpperCase() + str.slice(1)   // without template string
 }
 
 console.log(capitalize("this is a test"));
 console.log(capitalize("the Eiffel Tower"));
 console.log(capitalize("/index.html"));

/*
"this is a test" → "This is a test"
"the Eiffel Tower" → "The Eiffel Tower"
"/index.html" → "/index.html"
*/

Answer 64

The simplest solution is:

let yourSentence = 'it needs first letter upper case';

yourSentence.charAt(0).toUpperCase() + yourSentence.substr(1);

or:

yourSentence.charAt(0).toUpperCase() + yourSentence.slice(1);

or:

yourSentence.substr(0, 1).toUpperCase() + yourSentence.substr(1);

Answer 65

This code might work good in some cases:

function capitalizeFirstLetter(string) {
  return string.charAt(0).toUpperCase() + string.slice(1);
}

console.log(capitalizeFirstLetter('foo')); // Foo
// But if we had like this it won't work well
console.log(capitalizeFirstLetter('fOo')); // FOo

But if you really want to make sure, that there is only the first letter capitalized and the rest is built out of lowercase letters, you could adjust the code like this:

function capitalizeFirstLetter(string) {
  return string.charAt(0).toUpperCase() + string.slice(1).toLowerCase();
}
    
console.log(capitalizeFirstLetter('fOo')); // Foo

Answer 66

I use something along these lines in my development environment, especially when working with APIs like HTTP:

Suppose you have an HTTP header in which you'd like to capitalize every initial letter in its name and add the hyphen between its constituent words. You may achieve something like that using this basic and simple routine:

'access control allow origin'
    .replace(/\b\w/g, function (match) {
        return match.toUpperCase();
    })
    .split(' ')
    .join('-');

// Output: 'Access-Control-Allow-Origin'

It is not maybe the most elegant and attractive function definition out there, but it certainly gets the job done.

Answer 67

Like it:

function capitalize(string,a) {
    var tempstr = string.toLowerCase();
    if (a == false || a == undefined)
        return tempstr.replace(tempstr[0], tempstr[0].toUpperCase());
    else {
        return tempstr.split(" ").map(function (i) { return i[0].toUpperCase() + i.substring(1) }).join(" ");
    }
}


capitalize('stack overflow yeah!',true)); //Stack Overflow Yeah!

capitalize('stack stack stack stack overflow yeah!'));//Stack overflow yeah!

https://jsfiddle.net/dgmLgv7b/

Answer 68

A one-liner:

'string'.replace(/(^[a-z])/,function (p) { return p.toUpperCase(); } )

Answer 69

Firstly, I just wanted to clear up what capitalize means in this context. "This String Is Capitalized" Reliable source

You can see from the example provided this is not what the OP is looking for. What it should say is "How do I make the first letter of a string uppercase" (Not capitalize string)

function ucfirst (str) {
    return typeof str != "undefined" ? (str += '', str[0].toUpperCase() + str.substr(1)) : '';
}

Explained

typeof str != "undefined" // Is str set
? // true
str += '' // Turns the string variable into a string
str[0].toUpperCase() // Get the first character and make it upper case
+ // Add
str.substr(1) // String starting from the index 1 (starts at 0)
: // false
''; // Returns an empty string

This will work with any argument or no argument at all.

undefined         === ""
""                === ""
"my string"       === "My string"
null              === "Null"
undefined         === "";
false             === "False"
0                 === "0"
true              === "True"
[]                === ""
[true,0,"",false] === "True,0,,false"

Answer 70

function capitalizeEachWord(str) {
    return str.replace(/\w\S*/g, function(txt) {
        return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase();
    });
}

document.write(capitalizeEachWord('foo BAR God bAD'));

Answer 71

A small improvement - every word in titlecase.

String.prototype.toTitleCase = function(){
    return this.replace(/\b(\w+)/g, function(m,p){ return p[0].toUpperCase() + p.substr(1).toLowerCase() });
}

var s = 'heLLo, wOrLD!';
console.log(s.toTitleCase()); // Hello, World!

Answer 72

One liner ("inputString can be set to any string"):

inputString.replace(/.{1}/, inputString.charAt(0).toUpperCase())

Answer 73

This one is simple

const upper = lower.replace(/^\w/, c => c.toUpperCase());

Answer 74

1. We'll be using CSS to achieve this. It can also be set from an external CSS.

<span text-transform="capitalize ">The first letter of each word becomes an upper case</span>

2. Using vanilla JavaScript, we could do:

let string = "test case"

string = string[0].toUpperCase() + string.substring(1)
//return "Test case"

Explanation</b/>:

string[0].toUpperCase(): converts the first letter in the string to upper case

string.substring(1): deletes the first letter in the string and returns the remaining characters

text-transform="capitalize": make the first letter of each word in this tag upper case. If you use 'uppercase' as the value of text-transform, every letter in the tag will be a capital letter

Answer 75

Any type of string can convert --

YoUrStRiNg → Yourstring

var str = yOuRsTrING.toLowerCase(); // Output: yourstring
str.charAt(0).toUpperCase() + str.slice(1); // Output: Y + ourstring = Yourstring

Answer 76

You can do str.replace(str[0], str[0].toUpperCase())

Check this example:

let str = "hello WORLD"
let newStr = str.replace(str[0], str[0].toUpperCase())

console.log("str: ", str)
console.log("newStr: ", newStr)

Answer 77

Okay, so I am new to JavaScript. I wasn't able to get the above to work for me. So I started putting it together myself. Here's my idea (about the same, different and working syntax):

String name = request.getParameter("name");
name = name.toUpperCase().charAt(0) + name.substring(1);
out.println(name);

Here I get the variable from a form (it also works manually):

String name = "i am a Smartypants...";
name = name.toUpperCase().charAt(0) + name.substring(1);
out.println(name);

Output: "I am a Smartypants...";

Answer 78

The function takes two arguments:

start - the start index;
length - the length of substring to capitalise

String.prototype.subUpper = function () {
    var result = this.toString();
    var start = 0;
    var length = 1;
    if (arguments.length > 0) {
        start = arguments[0];
        if (start < this.length) {
            if (arguments.length > 1) {
                length = arguments[1];
            }
            if (start + length > this.length) {
                length = this.length - start;
            }
            var startRest = start + length;
            var prefix = start > 0 ? this.substr(0, start) : String.empty;
            var sub = this.substr(start, length);
            var suffix = this.substr(startRest, this.length - startRest);
            result = prefix + sub.toUpperCase() + suffix;
        }
    }
    return result;
};

Answer 79

I have been trying to do same (that is; capitalize the first letter in a string while it is being typed) using jQuery. I searched all through the web for the answer but couldn't find it. However I was able to get a work around using the on() function in jQuery like so:

$("#FirstNameField").on("keydown",function(e){
    var str = $("#FirstNameField").val();
    if(str.substring()===str.substring(0,1)){
        $("#FirstNameField").val(str.substring(0,1).toUpperCase());
    } 
});

This function actually capitalizes the first letter while the data entrant is typing continuously.

Answer 80

The currently voted answer is right, but it doesn't trim or check the length of the string before capitalising the first character.

String.prototype.ucfirst = function(notrim) {
    s = notrim ? this : this.replace(/(?:(?:^|\n)\s+|\s+(?:$|\n))/g,'').replace(/\s+/g,' ');
    return s.length > 0 ? s.charAt(0).toUpperCase() + s.slice(1) : s;
}

Set the notrim argument to prevent trimming the string first:

'pizza'.ucfirst()         => 'Pizza'
'   pizza'.ucfirst()      => 'Pizza'
'   pizza'.ucfirst(true)  => '   pizza'

Answer 81

This does the same action:

var newStr = string.slice(0,1).toUpperCase() + string.slice(1);

Answer 82

If there's Lodash in your project, use upperFirst.

Answer 83

Capitalize First Word: Shortest

text.replace(/(^.)/, m => m.toUpperCase())

---

Capitalize Each Word: Shortest

text.replace(/(^\w|\s\w)/g, m => m.toUpperCase());

If you want to make sure the rest is in lowercase:

text.replace(/(^\w|\s\w)(\S*)/g, (_,m1,m2) => m1.toUpperCase()+m2.toLowerCase())

Answer 84

Capitalizing the first letter with validation

function capitalizeFirstLetter(str) {
    return (str && typeof str === 'string') ? (str.charAt(0).toUpperCase() + str.slice(1)) : "";
}

Testing

console.log(capitalizeFirstLetter(0)); // Output: ""
console.log(capitalizeFirstLetter(null)); // Output: ""
console.log(capitalizeFirstLetter("test")); // Output: "Test"
console.log(capitalizeFirstLetter({})); // Output: ""

Answer 85

I know this is an old question with a lot of answers but here's my quick snippet.

const capitalize = (str) => str?.split('').map( (e, i) => i === 0 ? e.toUpperCase() : e ).join('')

Answer 86

Solution for Cannot read property 'charAt' of undefined

const capitalize = (string) => {
        return string ? string.charAt(0).toUpperCase() + string.slice(1) : "";
    }

console.log(capitalize("i am a programmer")); // I am a programmer

Answer 87

This is what I use religiously:

function capitalizeMe(str, force){
    str = force ? str.toLowerCase() : str;
    return str.replace(/(\b)([a-zA-Z])/g,
        function(firstLetter){
            return firstLetter.toUpperCase();
        });
}


var firstName = capitalizeMe($firstName.val());

Answer 88

function cap(input) {
    return input.replace(/[\.\r\n\t\:\;\?\!]\W*(\w)/g, function(match, capture) {
         // For other sentences in the text
         return match.toUpperCase();
    }).replace(/^\W*\w/, function(match, capture) {
        // For the first sentence in the text
        return match.toUpperCase();
    });;
}

var a = "hi, dear user. it is a simple test. see you later!\r\nbye";
console.log(cap(a));
// Output: Hi, dear user. It is a simple test. See you later!
// Bye

Answer 89

Another way using RamdaJs, the functional programming way:

firstCapital(str){
    const fn = p => R.toUpper(R.head(p)) + R.tail(p);
    return fn(str);
}

With multiple words in a string:

firstCapitalAllWords(str){
    const fn = p => R.toUpper(R.head(p)) + R.tail(p);
    return R.map(fn,R.split(' ', str)).join(' ');
}

Answer 90

Just because you can, doesn't mean you should, however. It requires ECMAScript 6 as the code uses array destructuring.

const capitalizeFirstLetter = s => {
  const type = typeof s;
  if (type !== "string") {
    throw new Error(`Expected string, instead received ${type}`);
  }

  const [firstChar, ...remainingChars] = s;

  return [firstChar.toUpperCase(), ...remainingChars].join("");
};

Answer 91

The method will take a value and then split it to have an array of string.

const firstLetterToUpperCase = value => {
 return value.replace(
    value.split("")["0"], // Split stirng and get the first letter 
    value
        .split("")
        ["0"].toString()
        .toUpperCase() // Split string and get the first letter to replace it with an uppercase value
  );
};

Answer 92

EDIT : I like this one :

yourString.replace(/(^[a-z])/i, (str, firstLetter) => firstLetter.toUpperCase())

Answer 93

To capitalize all words:

Typescript version:

const capitalize = (str:string)=>{
        // Split into words
        const words = str.split(" ");
        const resWords:string[] = [];
        // loop over words, slicing and capitalizing the first letter of each word.
        words.forEach(word => {
            const letterOne = word.slice(0, 1);
            const upperCaseLetterOne = letterOne.toUpperCase();
            const otherLetters = word.slice(1);
            const newWord = upperCaseLetterOne+otherLetters
            resWords.push(newWord)
        });
        // Turn it back into a human-readable string.
        return resWords.join(" ");
    }

Javascript version:

const capitalize = (str)=>{
        // Split into words
        const words = str.split(" ");
        const resWords = [];
        // loop over words, slicing and capitalizing the first letter of each word.
        words.forEach(word => {
            const letterOne = word.slice(0, 1);
            const upperCaseLetterOne = letterOne.toUpperCase();
            const otherLetters = word.slice(1);
            const newWord = upperCaseLetterOne+otherLetters
            resWords.push(newWord)
        });
        // Turn it back into a human-readable string.
        return resWords.join(" ");
    }

You can use it like this:

const bookTitle = "my awesome book";
const displayBookTitle = capitalize(bookTitle);
console.log(displayBookTitle) // My Awesome Book

To capitalize the first word:

Typescript:

const capitalize = (str:string)=>{
    return str.charAt(0).toUpperCase() + str.slice(1)
}

Javascript:

const capitalize = (str)=>{
    return str.charAt(0).toUpperCase()+str.slice(1);
}

You use it like so:

console.log(capitalize("foo bar")) // Foo bar

Answer 94

Including this answer because this is a one line answer using spread operator. Not as perfomant as other answers. But still does the job without modifiying the original string.

const [firstLetter, ...rest] = "hello world";
console.log(`${firstLetter.toUpperCase()}${rest.join('')}`);

Answer 95

I don't see any other answers mentioning Intl.Segmenter, which "enables locale-sensitive text segmentation" -- meaning you can reliably identify the first character when dealing with characters composed from multiple code points. The big caveat with relying on it in browsers is the lack of Firefox support, see https://caniuse.com/mdn-javascript_builtins_intl_segmenter_segment & https://bugzilla.mozilla.org/show_bug.cgi?id=1423593.

See How can I get a character array from a string? for more details.

There are many excellent answers here already, so I'm solely going to focus on splitting by character.

Using the following test string, which is composed of 9 characters / 15 code points / 20 code units:

const str = '-‍‍-நி-깍-葛';

Naive, split

str.split('');
// (20) ["\ud83d", '\udc05', '-', '\ud83d', '\udc68', '‍', '\ud83d', '\udc69', '‍', '\ud83d', '\udc67', '-', 'ந', 'ி', '-', '깍', '-', '葛', '\udb40', '\udd00']

Slightly better, spread operator

[...str]
// (15) ["", '-', '', '‍', '', '‍', '', '-', 'ந', 'ி', '-', '깍', '-', '葛', '']

Intl.Segmenter (in supported browsers)

[...new Intl.Segmenter().segment(str)].map((g) => g.segment);
// (9) ["", '-', '‍‍', '-', 'நி', '-', '깍', '-', '葛']

graphemer 1.4.0

import Graphemer from 'graphemer';
const splitter = new Graphemer();
splitter.splitGraphemes(str);
// (9) ["", '-', '‍‍', '-', 'நி', '-', '깍', '-', '葛']

lodash 4.17.10

import _ from 'lodash';
_.split(str, '');
// (11) ["", '-', '‍‍', '-', 'ந', 'ி', '-', '깍', '-', '葛', '']

fabric.js v6.0.0-beta10 graphemeSplit (internal function)

import { graphemeSplit } from './fabric_graphemeSplit';
graphemeSplit(str);
// (15) ["", '-', '', '‍', '', '‍', '', '-', 'ந', 'ி', '-', '깍', '-', '葛', '']

@formatjs Intl.Segmenter 11.4.2 polyfill

await import('@formatjs/intl-segmenter/polyfill-force');
[...new Intl.Segmenter().segment(str)].map((g) => g.segment);
// (9) ["", '-', '‍‍', '-', 'நி', '-', '깍', '-', '葛']

Editable comparison: https://stackblitz.com/edit/stackblitz-typescript-lrag9u?devToolsHeight=90&file=index.ts

Answer 96

Here is the nice and cleaner version;

var str = '';
return str.replace(new RegExp('^'+str[0]+''), str[0].toUpperCase());

Results:

this is a test --> This is a test

Answer 97

I prefer to use a solution oriented to a functional programming (mapping an array):

Array.from(str).map((letter, i) => i === 0 ? letter.toUpperCase() : letter ).join('');

Answer 98

If you need to have all words starting with a capital letter, you can use the following function:

const capitalLetters = (s) => {
    return s.trim().split(" ").map(i => i[0].toUpperCase() + i.substr(1)).reduce((ac, i) => `${ac} ${i}`);
}

Example:

console.log(`result: ${capitalLetters("this is a test")}`)
// Result: "This Is A Test"

Answer 99

You should do like that:

let text = "lower case";
text = text.charAt(0).toUpperCase() + text.substring(1, text.length);

Answer 100

// capitalize only first character of multi words
var cfc = (str,fs=' ',es=' ')=>{ //str = string, fs = first separator, es = end separator
    var str = str.split(fs);
    var str2=[];
    str.find((item)=>{
        const a = item.charAt(0).toUpperCase()+item.slice(1).toLowerCase();
        str2.push(a);
    });
    return str2.join(es);
}
const str = "stRing1#sTRIng2#strING3";
console.log(cfc(str,'#','@')); // output: String1@String2@String3
console.log(cfc(str,'#',' ')); // output: String1 String2 String3

Answer 101

In the loop :

function capitalizeFirstIterative(array) {
    let res = [];
    for (let index = 0; index < array.length; index++) {
        const element = array[index];
        res.push(element.charAt(0).toUpperCase() + element.slice(1));
    }
    return res;
}

Recursively :

function capitalizeFirst (array) {
  if (array.length === 1) {
    return [array[0][0].toUpperCase() + array[0].substr(1)];
  }
  const res = capitalizeFirst(array.slice(0, -1));
  const string = array.slice(array.length - 1)[0][0].toUpperCase() + array.slice(array.length-1)[0].substr(1);
  res.push(string);
  return res;
}

Answer 102

try this one line fix

text[0].toUpperCase() + text.substring(1)

function getCapitalizedText(text) {
  return text[0].toUpperCase() + text.substring(1)
}

we can call this "getCapitalizedText" any number of times by passing the text.