Cloning an object using today's JavaScript: ECMAScript 2015 (formerly known as ECMAScript 6)
var original = {a: 1};
// Method 1: New object with original assigned.
var copy1 = Object.assign({}, original);
// Method 2: New object with spread operator assignment.
var copy2 = {...original};
Old browsers may not support ECMAScript 2015. A common solution is to use a JavaScript-to-JavaScript compiler like Babel to output an ECMAScript 5 version of your JavaScript code.
As pointed out by @jim-hall, this is only a shallow copy. Properties of properties are copied as a reference: changing one would change the value in the other object/instance.