How to capitalize the first letter of a word using JavaScript for the novice developer

There are several ways to format a string but most common ones involve the handling of capitalization. The follow two cases format a string using the infamous string methods: “replace()”, “toLowerCase()”, and “toUpperCase()”.

Case 1: Capitalize only the first character of a string

This one is pretty obvious.

let str = "this Is A StrinG!";
let newstr = str.replace(  /^[a-z]{1}/igm,function(m){return m.toUpperCase()});
//Output:  This Is A StrinG!

Case 2: Capitalize only the first character and force the rest of string to be in lowercase

let str = "this Is A StrinG!
let newstr = str.toLowerCase().replace(/^[a-z]{1}/igm,function(m){return m.toUpperCase()});
//Output:  This is a string!

Try it here:

Note: You can omit the {1} as the default will only match the first character, but it’s there to guarantee that you only want one letter. If you want the first two characters, then replace it with {2}, etc.

Hope this helps. Happy coding!

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