Object literals

ES6 makes some improvements to object literals. There are several improvements, but the one you'll see most is the implicit naming of object properties. In ES5 it would be as follows:

var name = ‘Burak’;
var title = ‘Author’;
var object = {name: name, title: title};

In ES6, if the property name and the variable name are the same as the preceding one, you can simplify it to the following:

const name = ‘Burak’;
const title = ‘Author’;
const object = {name, title};

Additionally, ES6 introduces the object spread operator, which simplifies shallow object merges. For instance, take a look at the following code in ES5:

function combinePreferences(userPreferences) {
 var defaultPreferences = {size: ‘large’, mode: ‘view’};
 return Object.assign({}, defaultPreferences, userPreferences);
}

The preceding code will create a new object from defaultPreferences, and merge in properties from userPreferences. Passing an empty object to the Object.assign instance first parameter ensures that we create a new object rather than overwriting defaultPreferences (which isn't an issue in the preceding example, but is an issue in real-life use cases).

And now, let's take a look at the same in ES6:

function combinePreferences(userPreferences) {
 var defaultPreferences = {size: ‘large’, mode: ‘view’};
 return {...defaultPreferences, ...userPreferences};
}

This approach does the same as the ES5 example, but is quicker and easier to read in my opinion than the Object.assign method. Developers familiar with React and Redux, for instance, often use the object spread operator when managing reducer state operations.