JavaScript numeric separators

Question

Some languages, like Java and C++, allow you to use numeric separators. To improve readability, you can group digits per thousand:

1_000_000_000

But not only per thousand; you can use it anywhere really. Say you have some value in centimeters. Separating it like this makes it easier for humans to read it as meters:

10_00  // 10 meters

Isn't there any way to accomplish this in JavaScript?

How on earth did this not get flagged as "opinion" and shut down immediately??? — AntonOfTheWoods
– AntonOfTheWoods, Commented Oct 9, 2024 at 2:53

Lucio Paiva · Accepted Answer · 2024-10-21 14:19:27Z

22

This feature is now added as part of ES2021.

And it works for any numeric base:

const decimal = 1_234;
const binary = 0b1000_0101;
const hex = 0x12_34_56_78;

It is supported by all major browsers (Chrome, Firefox, Edge, Safari, Opera) (source 1, source 2). And if you're working on the server side, Node.js v12.5.0 is already supporting it. Electron too.

edited Oct 21, 2024 at 14:19

answered Nov 21, 2019 at 1:36

Lucio Paiva

21.1k11 gold badges88 silver badges110 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Mix Master Mike Over a year ago

I'm trying to make this work with my app but I'm getting a Failed to compile error. I'm using ecma version 2018. What am I missing?

Lucio Paiva Over a year ago

@MixMasterMike this is not part of ECMAScript 2018 (not even 2019). It is a stage 3 proposal, not yet ready for release. I edited my answer to add that info. You will only be able to get this feature via v8 and projects that use it (Chrome, Nodejs, Electron, etc). Whatever the platform you're using, be sure to check if it uses at least v8 7.5. Well, it looks like Babel also supports it (see other answer).

Peter Mortensen · Accepted Answer · 2022-05-11 18:11:27Z

1

It sounds interesting. I found this worked on the latest version of Chrome.

Babel also supports it in stage-0. Then you can use Babel to transpile to ECMAScript 2015 (ES6).

Try it on Babel.

edited May 11, 2022 at 18:11

Peter Mortensen

31.2k22 gold badges111 silver badges134 bronze badges

answered Nov 21, 2019 at 5:25

Long Nguyen Duc

1,3451 gold badge10 silver badges13 bronze badges

Comments

Peter Mortensen · Accepted Answer · 2022-05-11 18:05:50Z

0

Constants are better for reading in some cases:

const G = 1**9;
const M = 1**6;
const k = 1**3;
const cm = 0.01;

var size = 5 * G;
var count = 10 * k;
var length = 100 * cm;

edited May 11, 2022 at 18:05

Peter Mortensen

31.2k22 gold badges111 silver badges134 bronze badges

answered Nov 21, 2019 at 5:12

Crutch Master

1895 bronze badges

1 Comment

user1559679 Over a year ago

I like that, but it would be powers of 10, not 1: const M = 10**6;

Collectives™ on Stack Overflow

JavaScript numeric separators

3 Answers 3

2 Comments

Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

2 Comments

Comments

1 Comment

Linked

Related