ECMAScript 6 provides a concise form for defining object literal methods and properties. This syntax can make defining complex object literals much cleaner.

Here are a few common examples using the ES5 syntax:

const x = 1, y = 2, z = 3;
// properties
const foo = {
    x: x,
    y: y,
    z: z,
};

// methods
const foo = {
    a: function() {},
    b: function() {}
};

The ES6 equivalent syntax is::

// properties
const foo = {x, y, z};

// methods
const bar = {
    a() { return 1 },
    b() { return 2 }
};

NOTE: The shorthand properties are equivalent to function expressions. Meaning that they do not bind their own this inside their bodies. It is still possible to access properties from the object inside a shorthand member function:

const object = {
    x: 1,
    getX() {
        return this.x // valid
    }
}

Bad Practice

const foo = {
    bar: function () { return 1 }
};

Recommended

const foo = {
    bar() { return 1 }
}