@johngw/stream
Version:
Reactive programming tools using the WHATWG Streams API.
68 lines • 1.81 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.some = void 0;
const Stream_1 = require("@johngw/stream-common/Stream");
/**
* Runs every chunk through a predicate. If anything suceeds the
* predicate, `true` is queued and the stream terminated.
* Otherwise this will wait for the entire stream to finish
* before queuing `false`.
*
* @group Transformers
* @see {@link every:function}
* @example
* When every chunk failes the predicate.
* ```
* --1--2--3--4--5--6--7--8--9-|
*
* every((x) => x > 10)
*
* ----------------------------F-|
* ```
*
* When something passes the predicate.
* ```
* --1--2--3--4--5--6--X
*
* every((x) => x > 5)
*
* -----------------T--|
* ```
*
* A `flushes` stream can be used to force the transformer to queue
* it's current state downstream.
*
* ```
* --1--2--3--4--5--6--7--8--9-|
*
* some((x) => x > 10, { flushes:
* -----------N-----------------
* })
*
* -----------F----------------F-|
*/
function some(predicate, options) {
const abortController = new AbortController();
return new TransformStream({
start(controller) {
(0, Stream_1.pipeFlushes)(() => controller.enqueue(false), (error) => controller.error(error), { ...options, signal: abortController.signal });
},
async transform(chunk, controller) {
try {
if (await predicate(chunk)) {
controller.enqueue(true);
controller.terminate();
}
}
catch (error) {
controller.error(error);
}
},
flush(controller) {
controller.enqueue(false);
abortController.abort();
},
});
}
exports.some = some;
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