how to make uppercase in first word using javascript 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: javascript uppercase first character of each word

const uppercaseWords = str => str.replace(/^(.)|\s+(.)/g, c => c.toUpperCase());

// Example
uppercaseWords('hello world');      // 'Hello World'