blue-iterate
Version:
A collection of streams that work well with promises (through, map, reduce). Through2 with promise support
64 lines (63 loc) • 2.76 kB
JavaScript
;
var __await = (this && this.__await) || function (v) { return this instanceof __await ? (this.v = v, this) : new __await(v); }
var __asyncGenerator = (this && this.__asyncGenerator) || function (thisArg, _arguments, generator) {
if (!Symbol.asyncIterator) throw new TypeError("Symbol.asyncIterator is not defined.");
var g = generator.apply(thisArg, _arguments || []), i, q = [];
return i = {}, verb("next"), verb("throw"), verb("return"), i[Symbol.asyncIterator] = function () { return this; }, i;
function verb(n) { if (g[n]) i[n] = function (v) { return new Promise(function (a, b) { q.push([n, v, a, b]) > 1 || resume(n, v); }); }; }
function resume(n, v) { try { step(g[n](v)); } catch (e) { settle(q[0][3], e); } }
function step(r) { r.value instanceof __await ? Promise.resolve(r.value.v).then(fulfill, reject) : settle(q[0][2], r); }
function fulfill(value) { resume("next", value); }
function reject(value) { resume("throw", value); }
function settle(f, v) { if (f(v), q.shift(), q.length) resume(q[0][0], q[0][1]); }
};
Object.defineProperty(exports, "__esModule", { value: true });
if (Symbol.asyncIterator === undefined) {
(Symbol.asyncIterator) = Symbol.for('asyncIterator');
}
function _parallelMap(concurrency, func, iterable) {
return __asyncGenerator(this, arguments, function* _parallelMap_1() {
const concurrentWork = new Set();
const results = [];
let ended = false;
const queueNext = () => {
const nextVal = iterable.next().then(async ({ done, value }) => {
if (done) {
ended = true;
}
else {
const mappedValue = await func(value);
results.push(mappedValue);
}
concurrentWork.delete(nextVal);
});
concurrentWork.add(nextVal);
};
for (let i = 0; i < concurrency; i++) {
queueNext();
}
while (true) {
if (results.length) {
yield results.shift();
if (!ended) {
queueNext();
continue;
}
}
if (concurrentWork.size === 0) {
return;
}
yield __await(Promise.race(concurrentWork));
}
});
}
function parallelMap(concurrency, func, iterable) {
if (func === undefined) {
return curriedFunc => parallelMap(concurrency, curriedFunc);
}
if (iterable === undefined) {
return curriedIterable => parallelMap(concurrency, func, curriedIterable);
}
return _parallelMap(concurrency, func, iterable);
}
exports.parallelMap = parallelMap;