Add Two Promises | #2723 | LeetCode Solution
Author: neptune | 12th-Sep-2023
Problem : Add Two Promises | #2723 | 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 [result1, result2] = await Promise.all([promise1, promise2]);
return Promise.resolve(result1 + result2);
};
/**
* addTwoPromises(Promise.resolve(2), Promise.resolve(2))
* .then(console.log); // 4
*/
Explanation:
Let's break down the code step by step:
1. `addTwoPromises` is a function that takes two promises, `promise1` and `promise2`, as arguments.
2. Inside the `addTwoPromises` function:
- `await Promise.all([promise1, promise2]);` - This line uses `Promise.all` to wait for both `promise1` and `promise2` to resolve. `Promise.all` takes an array of promises and returns a new promise that resolves with an array of their resolved values. In this case, `result1` will hold the resolved value of `promise1`, and `result2` will hold the resolved value of `promise2`.
- `return Promise.resolve(result1 + result2);` - After both promises have resolved, this line calculates the sum of `result1` and `result2`. Then, it returns a new promise using `Promise.resolve` that resolves with the sum as its value.
3. The `addTwoPromises` function is then called with two promises:
addTwoPromises(Promise.resolve(2), Promise.resolve(2))
- `Promise.resolve(2)` creates a promise that immediately resolves with the value `2`.
- `addTwoPromises` is called with two such promises.
4. `.then(console.log)` - This part of the code attaches a `.then` callback to the result of `addTwoPromises`. When the promise returned by `addTwoPromises` resolves (which will happen after both `Promise.resolve(2)` promises have resolved and their values have been added together), the `.then` callback is executed with the result as an argument.
5. `console.log` is used to output the result, so the sum of the two resolved values (`2 + 2`) is printed to the console, resulting in `4` being displayed.
In summary, this code defines a function `addTwoPromises` that takes two promises, waits for them to resolve using `Promise.all`, calculates their sum, and returns a new promise that resolves with the sum. When you call `addTwoPromises` with two promises that resolve to `2`, it returns a promise that eventually resolves to `4`, and `console.log` is used to print that value to the console.
#JavaScript #Hackerrank #Python #Motivation #AI #React.js #Testing #Interview #SQL #Selenium #LeetCode #Problem Solving #Machine learning #Java #GPT #AWS #API #IT #Algorithms #Github #Jobs #Microservice #Certifications #Projects #Google #Django #Story #Pip #Data Science #Postman #Health #Twitter #Elon Musk #Node.js
To Be Or Not To Be | #2704 | LeetCode SolutionAuthor: neptune | 03rd-Sep-2023
#JavaScript #LeetCode
Write a function that helps developers test their code. It should take in any value and return an object with the following two functions...
Apply Transform Over Each Element in Array | #2635 | LeetCode SolutionAuthor: neptune | 05th-Sep-2023
#JavaScript #LeetCode
Given an integer array `arr` and a mapping function `fn`, return a new array with a transformation applied to each element...
Counter | #2620 | LeetCode SolutionAuthor: neptune | 02nd-Sep-2023
#JavaScript #LeetCode
Given an integer n, return a counter function. This counter function returns n and then n + 1, n + 2, etc...
Function Composition | #2629 | LeetCode SolutionAuthor: neptune | 09th-Sep-2023
#JavaScript #LeetCode
Given an array of functions [f1, f2, f3, ..., fn], return a new function fn that is the function composition of the array of functions...
Counter 2 | #2665 | LeetCode SolutionAuthor: neptune | 04th-Sep-2023
#JavaScript #LeetCode
Write function 'createCounter' It accept an initial integer 'init' It should return an object with three functions- increment() , decrement(), reset()...
Arrow Functions in JavaScript | ES6Author: neptune | 26th-Mar-2023
#JavaScript #React.js
In this article, we will explore the syntax and usage of arrow functions in detail, along with some examples...
Array Reduce Transformation | #2626 | LeetCode SolutionAuthor: neptune | 09th-Sep-2023
#JavaScript #LeetCode
Given an integer array `nums` and a reducer function `fn`, and an initial value `init`, return a reduced array...
Different ways to handle state in React applicationsAuthor: neptune | 21st-Jun-2023
#JavaScript #React.js
This article explores different ways to manage states in React, including local component state, context API, and state management libraries like Redux...
Is Object Empty | #2727 | LeetCode | JavaScript SolutionAuthor: neptune | 01st-Sep-2023
#JavaScript #LeetCode
Given an object or an array, return if it is empty...
Filter Elements from Array | #2634 | LeetCode SolutionAuthor: neptune | 06th-Sep-2023
#JavaScript #LeetCode
Given an integer array `arr` and a filtering function `fn`, return a filtered array `filteredArr`...
Chunk Array | #2677 | LeetCode SolutionAuthor: neptune | 19th-Sep-2023
#JavaScript #LeetCode
Given an array arr and a chunk `size`, return a `chunked` array...
Managing Virtual Environments in React JavaScript ProjectsAuthor: neptune | 28th-Jun-2023
#JavaScript #React.js
Virtual environments are a valuable tool in React JavaScript projects as they allow developers to isolate dependencies, manage package versions, and maintain project consistency...
Allow One Function Call | #2666 | LeetCode SolutionAuthor: neptune | 11th-Sep-2023
#JavaScript #LeetCode
Given a function `fn`, return a new function that is identical to the original function except that it ensures `fn` is called at most once...
Memoize | #2634 | LeetCode SolutionAuthor: neptune | 12th-Sep-2023
#JavaScript #LeetCode
A memoized function is a function that will never be called twice with the same inputs. Instead it will return a cached value...
All You Need to Know About Pure Functions & Impure Functions in JavaScriptAuthor: neptune | 02nd-Apr-2023
#JavaScript #React.js
You should try to use pure functions whenever possible and avoid using impure functions unless necessary...
Array Prototype Last | #2619 | LeetCode SolutionAuthor: neptune | 20th-Sep-2023
#JavaScript #LeetCode
Write code that enhances all arrays such that you can call the `array.last()` method on any array and it will return the last element...
From REST to GraphQL: The Future of API DesignAuthor: neptune | 25th-Feb-2024
#JavaScript
Unlike traditional REST APIs, GraphQL provides a more flexible and intuitive approach to data querying and retrieval...
A Guide to Writing Clean, Readable, and Maintainable Code in JavaScriptAuthor: neptune | 23rd-Feb-2024
#JavaScript
By incorporating these principles into your coding practices, you contribute to creating code that is not only functional but also maintainable and easily understandable by your peers...
6 Brilliant JavaScript Frameworks for Every DeveloperAuthor: neptune | 16th-Feb-2024
#JavaScript
JavaScript's web development with frameworks like Synaptic.js for neural networks, OpenCV.js for multimedia processing, D3.js for dynamic data visualizations, Compromise.js for efficient NLP, ConvNet...
State in React: Component State and Controlling BehaviorAuthor: neptune | 21st-Feb-2024
#JavaScript #React.js
React, a popular JavaScript library for building user interfaces, introduces the concept of state and lifecycle methods to help developers manage the dynamic nature of components...
Decode Secret Language of React: Game-Changer for Web DevelopersAuthor: neptune | 25th-Feb-2024
#JavaScript #React.js
JSX is a syntax extension for JavaScript recommended by React for describing what the UI should look like...
View More