Case Conversion: Convert String to Lower Case, Upper Case and Title Case With JavaScript

Convert String to Lower Case :

In lower case, all letters of string appears in their small forms. Using the inbuilt toLowerCase() method we can easily convert given text to lower case letters with JavaScript.

var str = "JavaScript is Awesome";
console.log(str.toLowerCase()); 
// Output: javascript is awesome

Convert String to Upper Case :

In upper case, all letters of string appears in their capital forms Using the inbuilt toUpperCase() method a string can be converted to upper case letters with JavaScript.

var str = "JavaScript is Awesome";
console.log(str.toUpperCase()); 
// Output: JAVASCRIPT IS AWESOME

Convert String to Title Case :

In title case, first letter of every word in the string appears in capital form and rest of the letters remain in small form. There is no inbuilt method to convert a string to title case in JavaScript. But we can do this in various ways. I will show you one simple way, checkout the following example:

Try Yourself

function toTitleCase(str) {
  // Validate input
  if(!str) return;
  // Split the string into array of words
  var wordsArr = str.split(' ');
  var result = [];
  var word = "";
  for(var i = 0; i < wordsArr.length; i++){
    // Lower case each word
    word = wordsArr[i].toLowerCase(); 
    // Convert first character to upper case, append the rest
    result.push(word[0].toUpperCase() + word.slice(1));
  }
  // Convert array of title cased words to space separated string 
  return result.join(' '); 
}

var str = "JavaScript is Awesome";
var titleCased = toTitleCase(str);
console.log(titleCased);
// Output: Javascript Is Awesome

The function is self explanatory. I am using inbuilt array methods split(), join() and splice() to convert given string to title case. If you want to learn more about the array methods read this article.