Capitalize first letter of every word, and keep the rest in lowercase

Question

I'm learning Javascript here. My task as of right now is to take a given string and capitalize the beginning of each word, and IF the rest of the word is already caps, put it into lowercase.

What I have so far:

function titleCase(str){
    var arrayify = str.split('');
    arrayify.forEach(function(current, index){
        for (var x = 0; x < current; x++){
            var caps = current[x];
            return caps;
        } 
    });
}

My test strings:

I'm a little tea pot
sHoRt AnD sToUt
HERE IS MY HANDLE HERE IS MY SPOUT

What I've tried:

function titleCase(str){
   str.split(' ').map(s => chartAt(0).toUpperCase() + s.slice(1)).join(' '); 
}

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

Everytime I use the => it tells me that I need esversion:6 in order to run it.

My question, what am I doing wrong, and what would be the most idiomatic way to go about doing this?

Pictures to prove I'm not crazy:

First `titleCase` has no `return` statement and is missing the `.toLowerCase()` call. Second one forgot the `()` after `.toUpperCase`. They both have `chartAt(0)` instead of `charAt(0)`. — , Apr 28 '16 at 20:23
Oh, you're calling it on nothing. it should be `s.charAt(0)`. — , Apr 28 '16 at 20:28
@13aal: The second one also has an extra `}` in the middle, and is calling `.replace()` on `this` instead of `str`. — , Apr 28 '16 at 20:30
The `0 is read-only` is because strings are immutable, so you can't mutate individual characters. — , Apr 28 '16 at 20:42

score 1 · Accepted Answer · answered Apr 28 '16 at 20:36

To detail the issues with your existing solutions, they almost work but have the following problems:

function titleCase(str){
   // missing `s.`--------v    v---extra "t" 
   str.split(' ').map(s => chartAt(0).toUpperCase() + s.slice(1)).join(' '); 
//^---missing return statement |---missing toLowerCase() call---^
}

function titleCase(str) {
     // -----v--should be `str`
     return this.replace(/\w\S*/g, function(txt){
       // ------------v--extra "t" |----v--- extra "}"
       return txt.chartAt(0).toUpperCase} + txt.substr(1).toLowerCase();
       // ---missing `()` -------------^
     });
};

Here are the fixed versions:

function titleCase(str){
   return str.split(' ').map(s => s.charAt(0).toUpperCase() + s.slice(1).toLowerCase()).join(' ');
}

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

I have no idea what happened but it worked so thank you sir. — 13aal, Apr 28 '16 at 20:54

score 1 · Answer 2 · answered Apr 28 '16 at 20:55

You can change the function so instead of returning in the forEach loop it appends the result onto an existing variable to be returned at the end.

Get the character at the start of each array value, change it to uppercase and then add it to the rest of the value which has been converted to lowercase.

Example:

function titleCase(str){
    var arrayify = str.split(' ');
    var result = '';
    arrayify.forEach(function(item) {
        result += item.charAt(0).toUpperCase() + item.slice(1).toLowerCase() + ' ';
    });
    return result.slice(0, -1); // remove last whitespace
}

Capitalize first letter of every word, and keep the rest in lowercase

2 Answers2