How to swap case of characters in a string in JavaScript

In this Article we will go through how to swap case of characters in a string only using single line of code in JavaScript. This is a one-line JavaScript code snippet that uses one of the most popular ES6 features => Arrow Function.

Let's define this short function:

const swapCase = str => str.split('').map(c => (c === c.toLowerCase() ? c.toUpperCase() : c.toLowerCase())).join('');

swapCase('Hello World');      // 'hELLO wORLD'