| import { isPromise } from './isPromise.mjs'; |
| |
| /** |
| * Similar to Array.prototype.reduce(), however the reducing callback may return |
| * a Promise, in which case reduction will continue after each promise resolves. |
| * |
| * If the callback does not return a Promise, then this function will also not |
| * return a Promise. |
| */ |
| export function promiseReduce(values, callbackFn, initialValue) { |
| let accumulator = initialValue; |
| |
| for (const value of values) { |
| accumulator = isPromise(accumulator) |
| ? accumulator.then((resolved) => callbackFn(resolved, value)) |
| : callbackFn(accumulator, value); |
| } |
| |
| return accumulator; |
| } |