2821. Delay the Resolution of Each Promise 🔒

Description

Given an array functions and a number ms, return a new array of functions.

• functions is an array of functions that return promises.
• ms represents the delay duration in milliseconds. It determines the amount of time to wait before resolving or rejecting each promise in the new array.

Each function in the new array should return a promise that resolves or rejects after an additional delay of ms milliseconds, preserving the order of the original functions array.

The delayAll function should ensure that each promise from functions is executed with a delay, forming the new array of functions returning delayed promises.

 

Example 1:

Input: 
functions = [
   () => new Promise((resolve) => setTimeout(resolve, 30))
], 
ms = 50
Output: [80]
Explanation: The promise from the array would have resolved after 30 ms, but it was delayed by 50 ms, thus 30 ms + 50 ms = 80 ms.

Example 2:

Input: 
functions = [
    () => new Promise((resolve) => setTimeout(resolve, 50)),
    () => new Promise((resolve) => setTimeout(resolve, 80))
], 
ms = 70
Output: [120,150]
Explanation: The promises from the array would have resolved after 50 ms and 80 ms, but they were delayed by 70 ms, thus 50 ms + 70 ms = 120 ms and 80 ms + 70 ms = 150 ms.

Example 3:

Input: 
functions = [
    () => new Promise((resolve, reject) => setTimeout(reject, 20)), 
    () => new Promise((resolve, reject) => setTimeout(reject, 100))
], 
ms = 30
Output: [50,130]

 

Constraints:

• functions is an array of functions that return promises
• 10 <= ms <= 500
• 1 <= functions.length <= 10

Solutions

Solution 1

TypeScript

function delayAll(functions: Function[], ms: number): Function[] {
    return functions.map(fn => {
        return async function () {
            await new Promise(resolve => setTimeout(resolve, ms));
            return fn();
        };
    });
}

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