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naholyr/promise-all.js

Last active September 8, 2016 11:04
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Run promise-based async API in series or concurrency
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promise-all.js
// ( T1 => Promise<T2> ) => Array<T1> => Promise<Array<T2>>
export const concurrent = foo => vals =>
Promise.all(vals.map(foo))
export const series = foo => vals =>
vals.reduce((p, val) => p.then(rs => foo(val).then(r => rs.concat([val]))), Promise.resolve([]))
// Usage: promiseOfValues.then(promiseAll.concurrent(functionReturningAPromiseFromAValue))
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