Capitalize the first letter of each string

Question

I've been trying to capitalize the first letter of each word in a string, but it says TypeError: Cannot assign to read only property '0' of string 'i' . My logic looks fine but surely the way I'm doing this is not right. Any suggestions.

function titleCase(str) {
  str = str.toLowerCase();
  var word = str.split(" ");
  // console.log(word[0][0]);
  for (var i = 0; i < word.length - 1; i++) {
    word[i][0] = word[i][0].toUpperCase();
  }
  console.log(word);
  return word;
}

titleCase("I'm a little tea pot");

If you're not being paid by the character, try `s.replace(/\b\w/g,s=>s.toUpperCase())`. — RobG, Sep 30 '17 at 08:29

caramba · Accepted Answer · 2017-10-02T08:57:21.057

3

Try like so: (see comments in code)

function titleCase(str) {
  str=str.toLowerCase();
  var word = str.split(" ");
  for (var i=0; i < word.length; i++) {  // you don't need -1 here as you had
    word[i] = word[i].charAt(0).toUpperCase() + word[i].slice(1); // see changes in this line
  }
  console.log(word);
  return word;
}

titleCase("I'm a little tea pot");

edited Oct 02 '17 at 08:57

answered Sep 30 '17 at 07:54

caramba

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what does slice(1)do ? – Ahsan Alii Sep 30 '17 at 09:47
@AhsanAlii in this case it will remove the first letter (the lowercased one) which gets added with the uppercased one. – caramba Sep 30 '17 at 09:51

score 2 · Answer 2 · answered Sep 30 '17 at 08:30

2

Strings have a replace method that accepts a function:

var s = 'foo bar fum i am sparticus 23!!';

console.log(s.replace(/\b\w/g, function(s){return s.toUpperCase()}));

answered Sep 30 '17 at 08:30

RobG

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score 1 · Answer 3 · answered Sep 30 '17 at 07:54

You can directly convert your string into what you want by inbuilt array function. Using map function you will get it directly no need to run for loop.

("I'm a little tea pot")
.split(" ")
.map(function(d){
 return d[0].toUpperCase()+d.substring(1,d.length)
}).join(" ")

score 1 · Answer 4 · answered Sep 30 '17 at 07:55

You can combine split and map functions to achieve this.

function titleCase(str) {
  return str.toLowerCase().split(" ").map(function(word) {
    var _word = word.split("");
    _word[0] = _word[0].toUpperCase();
    return _word.join("");
  }).join(" ");
}

console.log(titleCase("I'm a little tea pot"));

Faly · Answer 5 · 2017-09-30T08:02:18.680

With split, array map and reduce:

var str = "I'm a little tea pot";
var res = str.split(" ")
             .map(word => word.charAt(0).toUpperCase() + word.substr(1))
             .reduce((m, o) => { m = m + " " + o; return m }, "")
console.log(res);

Join can be also used instead of reduce:

    var str = "I'm a little tea pot";
    var res = str.split(" ")
                 .map(word => word.charAt(0).toUpperCase() + word.substr(1))
                 .join(" ");
    console.log(res);

score 1 · Answer 6 · answered Sep 30 '17 at 08:02

You can use map function to create an array of modified words and join to recreate the string

function titleCase(str) {
  str = str.toLowerCase();
  var word = str.split(" ");

  var x = word.map(function(item) {
    return item.charAt(0).toUpperCase() + item.substring(1, item.length);
  }).join(" ");
  return x
}

console.log(titleCase("I'm a little tea pot"));

Using only CSS

#test {
  text-transform: capitalize
}

<div id="test"> I'm a little tea pot</div>

Capitalize the first letter of each string

6 Answers6