Aliases with JavaScript Destructuring

By  on  

Destructuring in JavaScript has totally changed the way JavaScript is written these days;  code is more concise to write but but, from a visual standpoint, the syntax of the language has changed so much.  Any good developer knows, however, that change is the constant we live in.

The basic idea behind destructuring in object literals is as follows:

const obj = { x: 1 };

// Grabs obj.x as { x }
const { x } = obj;

There are cases where you want the destructured variable to have a different name than the property name; in that case, you'll use a : newName to specify a name for the variable:

// Grabs obj.x as as { otherName }
const { x: otherName } = obj;

The syntax for specifying an alternate destructured name for an object property is simple and needed.  Destructuring had the capability to confuse developers, especially array destructuring and function argument destructuring, but this alias syntax is a simple trick to keep in your locker!

Recent Features

  • By
    From Webcam to Animated GIF: the Secret Behind chat.meatspac.es!

    My team mate Edna Piranha is not only an awesome hacker; she's also a fantastic philosopher! Communication and online interactions is a subject that has kept her mind busy for a long time, and it has also resulted in a bunch of interesting experimental projects...

  • By
    Page Visibility API

    One event that's always been lacking within the document is a signal for when the user is looking at a given tab, or another tab. When does the user switch off our site to look at something else? When do they come back?

Incredible Demos

  • By
    MooTools TwitterGitter Plugin

    Everyone loves Twitter. Everyone loves MooTools. That's why everyone should love TwitterGitter, a MooTools plugin that retrieves a user's recent tweets and allows the user to format them however the user would like. TwitterGitter allows the user to choose the number of...

  • By
    MooTools Star Ratings with MooStarRating

    I've said it over and over but I'll say it again:  JavaScript's main role in web applications is to enhance otherwise boring, static functionality provided by the browser.  One perfect example of this is the Javascript/AJAX-powered star rating systems that have become popular over the...

Discussion

  1. Always have to check your site first to see any updates. Love it david. That’s where good developers stand out. Always adapting to new changes. Just trying to get hang of destructing as i’m not the smartest one in the room.

  2. undefined alias

    Hello. I’m using an alias for my destructed object property. How can I handle the property when it’s undefined?
    Thanks.

  3. Jan

    I was looking for something like this. I wonder why the proposal for this feature didn’t follow the syntax of import statements.

    Example:

    const { x as otherName } = obj;
    
    • Memo

      this is the typescript syntax

  4. mark

    I don’t know why people call it an “alias”. If it were an alias, changing the variable would change the object property. E.g.

    let obj = { x: 1 }        
    let { x: x_notalias } = obj 
    x_notalias = 2                  // 2
    obj                             // { x: 1 }
    

    I think the only time you can have an alias in JavaScript is with reference types.

    let obj = { x: 1 }
    let obj_alias = obj
    obj_alias.x = 2
    obj                        // { x: 2 }
    
  5. Maksym Kulikovskiy

    When destructuring we use the word “alias” to refer to a differently named variable with the same value, rather than a different name that should reference the same variable.

Wrap your code in <pre class="{language}"></pre> tags, link to a GitHub gist, JSFiddle fiddle, or CodePen pen to embed!