31 lines
934 B
JavaScript
31 lines
934 B
JavaScript
'use strict';
|
|
const pLimit = require('p-limit');
|
|
|
|
class EndError extends Error {
|
|
constructor(value) {
|
|
super();
|
|
this.value = value;
|
|
}
|
|
}
|
|
|
|
// the input can also be a promise, so we `Promise.all()` them both
|
|
const finder = el => Promise.all(el).then(val => val[1] === true && Promise.reject(new EndError(val[0])));
|
|
|
|
module.exports = (iterable, tester, opts) => {
|
|
opts = Object.assign({
|
|
concurrency: Infinity,
|
|
preserveOrder: true
|
|
}, opts);
|
|
|
|
const limit = pLimit(opts.concurrency);
|
|
|
|
// start all the promises concurrently with optional limit
|
|
const items = Array.from(iterable).map(el => [el, limit(() => Promise.resolve(el).then(tester))]);
|
|
|
|
// check the promises either serially or concurrently
|
|
const checkLimit = pLimit(opts.preserveOrder ? 1 : Infinity);
|
|
|
|
return Promise.all(items.map(el => checkLimit(() => finder(el))))
|
|
.then(() => {})
|
|
.catch(err => err instanceof EndError ? err.value : Promise.reject(err));
|
|
};
|