@worker-tools/deno-kv-storage
Version:
An implementation of the StorageArea (1,2,3) interface for Deno with an extensible system for supporting various database backends.
84 lines • 2.8 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.MuxAsyncIterator = void 0;
// Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
const deferred_js_1 = require("./deferred.js");
/** The MuxAsyncIterator class multiplexes multiple async iterators into a
* single stream. It currently makes an assumption:
* - The final result (the value returned and not yielded from the iterator)
* does not matter; if there is any, it is discarded.
*/
class MuxAsyncIterator {
constructor() {
Object.defineProperty(this, "iteratorCount", {
enumerable: true,
configurable: true,
writable: true,
value: 0
});
Object.defineProperty(this, "yields", {
enumerable: true,
configurable: true,
writable: true,
value: []
});
// deno-lint-ignore no-explicit-any
Object.defineProperty(this, "throws", {
enumerable: true,
configurable: true,
writable: true,
value: []
});
Object.defineProperty(this, "signal", {
enumerable: true,
configurable: true,
writable: true,
value: (0, deferred_js_1.deferred)()
});
}
add(iterable) {
++this.iteratorCount;
this.callIteratorNext(iterable[Symbol.asyncIterator]());
}
async callIteratorNext(iterator) {
try {
const { value, done } = await iterator.next();
if (done) {
--this.iteratorCount;
}
else {
this.yields.push({ iterator, value });
}
}
catch (e) {
this.throws.push(e);
}
this.signal.resolve();
}
async *iterate() {
while (this.iteratorCount > 0) {
// Sleep until any of the wrapped iterators yields.
await this.signal;
// Note that while we're looping over `yields`, new items may be added.
for (let i = 0; i < this.yields.length; i++) {
const { iterator, value } = this.yields[i];
yield value;
this.callIteratorNext(iterator);
}
if (this.throws.length) {
for (const e of this.throws) {
throw e;
}
this.throws.length = 0;
}
// Clear the `yields` list and reset the `signal` promise.
this.yields.length = 0;
this.signal = (0, deferred_js_1.deferred)();
}
}
[Symbol.asyncIterator]() {
return this.iterate();
}
}
exports.MuxAsyncIterator = MuxAsyncIterator;
//# sourceMappingURL=mux_async_iterator.js.map