Leetcode•Oct 30, 2025
Add Two Promises
Hazrat Ali
Leetcode
Given two promises promise1 and promise2, return a new promise. promise1 and promise2 will both resolve with a number. The returned promise should resolve with the sum of the two numbers.
Example 1:
Input: promise1 = new Promise(resolve => setTimeout(() => resolve(2), 20)), promise2 = new Promise(resolve => setTimeout(() => resolve(5), 60)) Output: 7 Explanation: The two input promises resolve with the values of 2 and 5 respectively. The returned promise should resolve with a value of 2 + 5 = 7. The time the returned promise resolves is not judged for this problem.
Example 2:
Input: promise1 = new Promise(resolve => setTimeout(() => resolve(10), 50)), promise2 = new Promise(resolve => setTimeout(() => resolve(-12), 30)) Output: -2 Explanation: The two input promises resolve with the values of 10 and -12 respectively. The returned promise should resolve with a value of 10 + -12 = -2.
Solution
/**
* @param {Promise} promise1
* @param {Promise} promise2
* @return {Promise}
*/
var addTwoPromises = async function(promise1, promise2) {
const [val1, val2] = await Promise.all([promise1, promise2]);
return val1 + val2;
};