es-toolkit/docs/reference/function/before.md

before

Creates a new function that limits the number of times the given function (func) can be called.

Signature

function before<F extends (...args: any[]) => any>(n: number, func: F): F;

Parameters

• n (number): The number of times the returned function is allowed to call func before stopping.
  • If n is 0, func will not be called.
  • If n is a positive integer, func will be called up to n-1 times.
• func (F): The function to be called with the limit applied.

Returns

(F): A new function that:

• Tracks the number of calls.
• Invokes func until the n-1-th call.
• Returns undefined if the number of calls reaches or exceeds n, stopping further calls.

Error

Throws an error if n is negative.

Example

import { before } from 'es-toolkit/function';

const beforeFn = before(3, () => {
  console.log('called');
});

// Will log 'called'.
beforeFn();

// Will log 'called'.
beforeFn();

// Will not log anything.
beforeFn();