{"id":20569,"date":"2020-12-07T22:25:50","date_gmt":"2020-12-08T06:25:50","guid":{"rendered":"https:\/\/careerkarma.com\/blog\/?p=20569"},"modified":"2023-12-01T04:05:43","modified_gmt":"2023-12-01T12:05:43","slug":"javascript-spread-operator","status":"publish","type":"post","link":"https:\/\/careerkarma.com\/blog\/javascript-spread-operator\/","title":{"rendered":"JavaScript Spread Operator: A Guide"},"content":{"rendered":"\n

avaScript spread operator expands an array in syntax that accepts arguments. The spread operator is commonly used to duplicate objects, merge arrays or pass the contents of a list into a function.<\/em><\/p>\n\n\n\n

The spread operator. No, it\u2019s got nothing to do with toast. In JavaScript, the spread operator has a specific meaning: it\u2019s a way to access the contents of an iterable object. While this may not sound as fun as pasting a spread on toast, it\u2019s an incredibly useful tool to know about.\n\n<\/p>\n\n\n\n

In this guide, we\u2019re going to talk about the JavaScript spread operator and how it works. We\u2019ll walk through a few examples of common use cases to help you get started.<\/p>\n\n\n\n

What is the JavaScript Spread Operator?<\/h2>\n\n\n\n

A JavaScript spread operator lets you access the contents of an iterable object. The spread operator is a set of three dots (an ellipsis) followed by the name of the iterable you want to access. This operator was introduced in JavaScript ES6.<\/p>\n\n\n\n

The three types of iterable objects are arrays, object literals, and strings. Using a for loop, you can loop through all of these types of data and run a common process on them.<\/p>\n\n\n\n

Iterable objects are useful because you can execute the same process on them multiple times. You can loop through a string and replace certain characters. You can loop through an array and create a total of all the values stored in the array.<\/p>\n\n\n\n

The syntax for the spread operator is:<\/p>\n\n\n\n

var names = ["John", "Lisa", "Harry"];\nvar new_names = [...names, "Leslie"];\nconsole.log(new_names);<\/pre><\/div>\n\n\n\n
In this syntax, we use …names to pass the contents of our “names” list into a list called “new_names”. The “new_names” list contains all the items in the “names” list, as well as a new name: Leslie.<\/p>\n\n\n\n
Three common use cases for the spread operator are to:<\/p>\n\n\n\n