Most efficient code to add a dollar sign behind a negative/positive number in JS

Question

I have two prices, A and B, and I want to show A - B with a dollar sign.

Example:

A: 10, B: 30 => -$20
A: 40, B: 5  => $35

It is possible to use this function:

function minus(A, B) {
    return `${A-B < 0 && "-"}$${Math.abs(A-B)}`
}

I'am just wondering if it's the most efficient way (in terms of speed & performance) to do this, or there's a wiser (!) (and maybe faster) approach.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/NumberFormat — Martijn, Feb 28 '22 at 21:54
Optimisation at this level is not really worth it. First focus on the big parts. Shaving of 5ms isnt going to be noticable by anyone — Martijn, Feb 28 '22 at 21:54
[Which is faster?](https://ericlippert.com/2012/12/17/performance-rant/) — VLAZ, Feb 28 '22 at 21:56
@Martijn `Intl.NumberFormat` is Interesting. Never heard of it before. — Shahriar, Feb 28 '22 at 21:57
This is already the most efficient code. It runs at O(1). You can’t get more efficient than that. — Sebastian Simon, Feb 28 '22 at 21:59
[What is a plain English explanation of "Big O" notation?](https://stackoverflow.com/q/487258) — VLAZ, Feb 28 '22 at 22:03
@Shahriar Constant time. It doesn’t depend on input size. That’s what _efficiency_ is measured in and where it differs from _speed_. — Sebastian Simon, Feb 28 '22 at 22:09

score 0 · Answer 1 · answered Feb 28 '22 at 22:00

0

I didnt check if it is faster, but i prefer this approach:

(a, b) => String(a - b).replace(/^-?/, '$&\$')

just a matter of taste :)

answered Feb 28 '22 at 22:00

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Most efficient code to add a dollar sign behind a negative/positive number in JS

Example:

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