What are the differences between Promise.all() and Promise.race() in JavaScript?
Davide S

ThePromise.all() andPromise.race() methods in JavaScript are used with Promises to handle multiple asynchronous operations. Although they have similar syntax and work with multiple Promises, they have distinct behaviors and use cases. Here are the differences betweenPromise.all() andPromise.race(): 1. Behavior: -Promise.all(): -Promise.all() takes an array of Promises and returns a new Promise that fulfills when all the Promises in the array have fulfilled. The fulfillment value of the returned Promise is an array containing the fulfillment values of the input Promises, in the same order as the original array. -Promise.race(): -Promise.race() takes an array of Promises and returns a new Promise that fulfills or rejects as soon as any of the Promises in the array fulfills or rejects. The fulfillment or rejection value of the returned Promise is the fulfillment or rejection value of the first Promise that resolves. 2. Usage: -Promise.all(): - UsePromise.all() when you want to wait for all Promises to complete and retrieve all the results together. It is useful when you need to perform multiple asynchronous operations in parallel and wait for all of them to finish before proceeding. -Promise.race(): - UsePromise.race() when you want to execute multiple Promises concurrently but are interested only in the result of the first Promise that resolves. It is useful when you want to retrieve the fastest result or when you want to set a timeout for an operation. 3. Handling Rejections: -Promise.all(): - If any of the Promises passed toPromise.all() rejects, the returned Promise is immediately rejected with the reason of the first Promise that rejects. Other Promises continue to execute, but their results are ignored. -Promise.race(): - If any of the Promises passed toPromise.race() rejects, the returned Promise is rejected with the reason of the first Promise that rejects. It doesn't matter if other Promises are still pending or resolve later. 4. Example: -Promise.all(): - Waiting for multiple Promises to fulfill:

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       const promise1 = Promise.resolve('Result 1');
       const promise2 = Promise.resolve('Result 2');
       const promise3 = Promise.resolve('Result 3');

       Promise.all([promise1, promise2, promise3])
         .then((results) => {
           console.log(results); // Output: ['Result 1', 'Result 2', 'Result 3']
         });

-Promise.race(): - Retrieving the result of the fastest Promise:

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       const promise1 = new Promise((resolve) => setTimeout(resolve, 2000, 'Result 1'));
       const promise2 = new Promise((resolve) => setTimeout(resolve, 1000, 'Result 2'));

       Promise.race([promise1, promise2])
         .then((result) => {
           console.log(result); // Output: 'Result 2' (resolved faster)
         });

In thePromise.all() example, an array of Promises is passed toPromise.all(), and a new Promise is returned that fulfills with an array of all the fulfillment values. In thePromise.race() example, an array of Promises is passed toPromise.race(), and a new Promise is returned that fulfills or rejects with the result of the first Promise that resolves, regardless of the other Promises' states. Consider the specific requirements of your application and choose the appropriate method accordingly. UsePromise .all() when you need to wait for multiple Promises to complete together, and usePromise.race() when you want to retrieve the result of the fastest resolving Promise.

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