While Promise.all is the traditional way to run multiple asynchronous operations in JavaScript, it aborts the whole batch when any promise rejects, making it impossible to know which calls succeeded; Promise.allSettled overcomes this by waiting for all promises and providing a detailed status for each result.
Promise.all stops all concurrent operations when any promise rejects, leaving you unaware of which tasks succeeded; using Promise.allSettled instead lets you wait for every promise to settle, providing a detailed result array that distinguishes fulfilled values from rejected reasons, enabling resilient async workflows.
This article explains the limitations of Promise.all, demonstrates how Promise.allSettled handles both fulfilled and rejected promises without aborting the whole operation, and shows practical code examples for building more resilient JavaScript applications.
While Promise.all is a common way to run multiple promises concurrently, it fails when any promise rejects and offers no control over the number of simultaneous executions; this article explores its limitations and presents elegant alternatives such as Promise.allSettled, simple queue implementations, and libraries like p-limit for effective concurrency management.
Promise.allSettled enhances JavaScript concurrency by waiting for every promise to settle—whether fulfilled or rejected—so developers can retrieve all results and handle errors more flexibly, unlike Promise.all which aborts on the first rejection.
Promise.allSettled overcomes the fatal flaw of Promise.all by waiting for all promises to settle—whether fulfilled or rejected—returning a uniform result array that lets developers identify successful outcomes and handle failures without aborting the entire operation, enabling more resilient asynchronous code.
This article introduces several relatively obscure yet practical ES6 features—including Object.entries/Object.fromEntries, Symbol, WeakMap/WeakSet, Promise.allSettled, BigInt, Array.of/Array.from, and the .at and flat methods—explaining their purpose and providing code examples for each.
