38 lines
1.3 KiB
JavaScript
38 lines
1.3 KiB
JavaScript
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//#region src/promise/allKeyed.ts
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/**
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* Resolves an object of promises concurrently, returning an object with the same keys and resolved values.
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*
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* Similar to `Promise.all`, but accepts an object of promises instead of an array,
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* preserving the keys in the result. This makes it easy to destructure the resolved values
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* by name instead of relying on positional indices.
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*
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* Based on the [TC39 `Promise.allKeyed` proposal](https://github.com/tc39/proposal-await-dictionary).
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*
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* @template T - A record type where each value is a promise or a value.
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* @param {T} tasks - An object whose values are promises (or plain values) to resolve concurrently.
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* @returns {Promise<{ [K in keyof T]: Awaited<T[K]> }>} A promise that resolves to an object with the same keys and resolved values.
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*
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* @example
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* const { user, posts } = await allKeyed({
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* user: fetchUser(),
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* posts: fetchPosts(),
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* });
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*
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* @example
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* // Plain values are also supported
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* const result = await allKeyed({
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* a: Promise.resolve(1),
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* b: 2,
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* });
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* // { a: 1, b: 2 }
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*/
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async function allKeyed(tasks) {
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const keys = Object.keys(tasks);
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const values = await Promise.all(keys.map((key) => tasks[key]));
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const result = {};
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for (let i = 0; i < keys.length; i++) result[keys[i]] = values[i];
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return result;
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}
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//#endregion
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exports.allKeyed = allKeyed;
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