Another cool feature that also shipped with ES6 is variable renaming. November 15, 2016 ES6, JavaScript Edit Post Last post we took a look at an intro to destructuring. Imagine we have the data of a student including scores in three subjects(Maths, Elementary Science, English) represented in an object and we need to display some information based on this data.

Another cool feature that also shipped with ES6 is variable renaming. It works in a similar way as with Arrays. All Right Reserved.The JavaScript Tutorial website helps you learn JavaScript programming from scratch quickly and effectively. The object and array literal expressions provide an easy way to create ad hocpackages of data. The destructuring assignment uses similar syntax, but on the left-hand side of the assignment to define what values to unpack from the sourced variable.

You will also learn how to use it, when to use it and what to avoid.

It works as it should. For example:It’ll be simpler with the destructuring assignment with a default value:A typical way to solve this is to fallback the returned value of the The following function returns an array that contains an element which is another array, or nested array:Since the third element of the returned array is another array, you need to use the nested array destructuring syntax to destructure it, like this:Let’s see some practical examples of using the array destructuring assignment syntax.The array destructuring makes it easy to swap values of variables without using a temporary variable:In JavaScript, a function can return a value. But trust me, down the line these techniques really save a lot of time and make everything much easier to read when working with more complicated data structures.As a full time React developer I often see fellow colleagues give up on destructuring in event handlers due to a little confusion between destructuring and renaming variables.This is a simple React component that doesn’t really do much. This simple technique is amazing for writing cleaner, more readable JavaScript code. console. For example, if we only wanted to log I gave you a simple example above. This simple technique is amazing for writing cleaner, more readable JavaScript code. To explain the why of destructuring, we will consider a scenario which most of us might be familiar with or might have come across at one time or the other when coding in JavaScript. Otherwise don’t bother, it’s not worth it. breaking up the structure): ... // assign to existing variables using outer parentheses. This capability is similar to features present in languages such as Perl and Python. I want us to focus on the A common mistake that people make when trying to destructure variables is that they do this:And low and behold we get crazy errors when we try to do this. But it helps a lot when you start working with larger objects. The only problem with this is that it can cause some confusion to coders who are still getting to grips with everything that modern JavaScript has to offer. Let’s pretend we have an array of objects called It probably doesn’t look that amazing right now. Destructuring assignment is one of the features introduced in ES6. What if we had an object of objects? But hey! Imagine I extended my Now using our wonderful ES6 destructuring technique we can simplify our console log like this:This is a weird unusual example, but I hope you get the point. As a general rule of thumb, if destructuring stops you from repeating yourself then use it!

TypeScript supports the following forms of Destructuring (literally named after de-structuring i.e. However, you can return an array that contains multiple values, for example:And then you use the array destructuring assignment syntax to destructure the elements of the return array into variables:In this tutorial, you have learned how to use the ES6 destructuring assignment to destructure elements in an array into individual variables.Copyright © 2020 by JavaScript Tutorial Website. Destructuring objects and arrays is probably the most used feature in ES6 and for good reason. log (x, y, width, height); // 10,10,15,20.