Numeric literals with underscores in JavaScript

Question

I recently ran into this code and i was wandering if there is any difference of writing those numeric literals in JavaScript with or without underscores:

let number = 1234567890;
console.log(number);

let number2 = 123_4567_890;
console.log(number2);

Answer 1

The point of the Numeric Seperators is to visually aid developers when dealing with big numbers. They don't change the actual code or its meaning.

Answer 2

So after further reading, I see that ECMAScript 2021 has a new feature called Numeric separators which is used for larger numbers that are hard to read without separating them..

To improve readability, this feature enables underscores as separators in numeric literals as you can see in the following example for all kinds of numeric literals:

const readableMiliion = 1_000_000;
const regularMiliion = 1000000;

console.log(readableMiliion);
console.log(regularMiliion);     

const decimal = 1_000_000.220_720;
const binary = 0b01010110_00111000;
const hexa = 0x40_76_38_6A_73;

console.log(decimal);  
console.log(binary);  
console.log(hexa);  

More about Numeric separators can be found here: https://v8.dev/features/numeric-separators

Or here https://writingjavascript.com/what-are-numeric-separators