JavaScript: Reverse Arrays


Manipulating data is core to any programming language. JavaScript is no exception, especially as JSON has token over as a prime data delivery format. One such data manipulation is reversing arrays. You may want to reverse an array to show most recent transactions, or simple alphabetic sorting.

Reversing arrays with JavaScript originally was done via reverse but that would mutate the original array:

// First value:
const arr = ['hi', 'low', 'ahhh'];

// Reverse it without reassigning:
arr.reverse();

// Value:
arr (3) ['ahhh', 'low', 'hi']

Modifying the original array is a legacy methodology. To avoid this mutation, we’d copy the array and then reverse it:

const reversed = [...arr].reverse();

These days we can use toReversed to avoid mutating the original array:

const arr = ['hi', 'low', 'ahhh'];
const reversed = arr.toReversed(); // (3) ['ahhh', 'low', 'hi'];
arr; // ['hi', 'low', 'ahhh']

Avoiding mutation of data objects is incredibly important in a programming language like JavaScript where object references are meaningful.

  • CSS 3D Folding Animation
  • Facebook Open Graph META Tags

    It’s no secret that Facebook has become a major traffic driver for all types of websites.  Nowadays even large corporations steer consumers toward their Facebook pages instead of the corporate websites directly.  And of course there are Facebook “Like” and “Recommend” widgets on every website.  One…

  • Web Notifications API

    Every UI framework has the same set of widgets which have become almost essential to modern sites: modals, tooltips, button varieties, and notifications.  One problem I find is each site having their own widget colors, styles, and more — users don’t get a consistent experience.  Apparently the…

  • Introducing MooTools ScrollSide

    This post is a proof of concept post — the functionality is yet to be perfected. Picture this: you’ve found yourself on a website that uses horizontal scrolling instead of vertical scrolling. It’s an artistic site so you accept that the site scrolls left to right.


Latest articles

spot_imgspot_img

Related articles

Leave a reply

Please enter your comment!
Please enter your name here

spot_imgspot_img