@azure/core-sse
Version:
Implementation of the Server-sent events protocol for Node.js and browsers.
94 lines • 2.98 kB
JavaScript
;
// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.
Object.defineProperty(exports, "__esModule", { value: true });
exports.createStream = createStream;
exports.ensureAsyncIterable = ensureAsyncIterable;
const tslib_1 = require("tslib");
function createStream(asyncIter, cancel) {
const stream = iteratorToStream(asyncIter, cancel);
/** TODO: remove these polyfills once all supported runtimes support them */
return polyfillStream(stream, cancel);
}
function polyfillStream(stream, dispose) {
makeAsyncIterable(stream);
makeAsyncDisposable(stream, dispose);
return stream;
}
function makeAsyncDisposable(webStream, dispose) {
var _a;
(_a = Symbol.asyncDispose) !== null && _a !== void 0 ? _a : (Symbol.asyncDispose = Symbol("Symbol.asyncDispose"));
if (!webStream[Symbol.asyncDispose]) {
webStream[Symbol.asyncDispose] = () => dispose();
}
}
function makeAsyncIterable(webStream) {
if (!webStream[Symbol.asyncIterator]) {
webStream[Symbol.asyncIterator] = () => toAsyncIterable(webStream);
}
if (!webStream.values) {
webStream.values = () => toAsyncIterable(webStream);
}
}
function iteratorToStream(iterator, cancel) {
return new ReadableStream({
async pull(controller) {
const { value, done } = await iterator.next();
if (done) {
controller.close();
}
else {
controller.enqueue(value);
}
},
cancel,
});
}
function ensureAsyncIterable(stream) {
if (isReadableStream(stream)) {
makeAsyncIterable(stream);
return {
cancel: () => stream.cancel(),
iterable: stream,
};
}
else {
return {
cancel: async () => {
// socket could be null if the connection is already closed
if ("socket" in stream && stream.socket) {
stream.socket.end();
}
else {
stream.destroy();
}
},
iterable: stream,
};
}
}
function isReadableStream(body) {
return Boolean(body &&
typeof body.getReader === "function" &&
typeof body.tee === "function");
}
function toAsyncIterable(stream) {
return tslib_1.__asyncGenerator(this, arguments, function* toAsyncIterable_1() {
const reader = stream.getReader();
try {
while (true) {
const { value, done } = yield tslib_1.__await(reader.read());
if (done) {
return yield tslib_1.__await(void 0);
}
yield yield tslib_1.__await(value);
}
}
finally {
const cancelPromise = reader.cancel();
reader.releaseLock();
yield tslib_1.__await(cancelPromise);
}
});
}
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