capitalize string js code example

Example 1: javascript capitalize words

//capitalize only the first letter of the string. 
function capitalizeFirstLetter(string) {
    return string.charAt(0).toUpperCase() + string.slice(1);
}
//capitalize all words of a string. 
function capitalizeWords(string) {
    return string.replace(/(?:^|\s)\S/g, function(a) { return a.toUpperCase(); });
};

Example 2: uppercase javascript

var str = "Hello World!";
var res = str.toUpperCase();  //HELLO WORLD!

Example 3: capitalize first letter javascript

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

console.log(capitalizeFirstLetter('foo bar bag')); // Foo

Example 4: javascript capitalize first letter

const lower = 'this is an entirely lowercase string';
const upper = lower.charAt(0).toUpperCase() + lower.substring(1);

Example 5: capitalize in javascript

const name = 'flavio'
const nameCapitalized = name.charAt(0).toUpperCase() + name.slice(1)

Example 6: capitalize string js

With performance metrics...

// 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);
}