kopia lustrzana https://github.com/FacilMap/facilmap
75 wiersze
2.3 KiB
TypeScript
75 wiersze
2.3 KiB
TypeScript
import { ReadableStream, TransformStream } from "stream/web";
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export async function asyncIteratorToArray<T>(iterator: AsyncIterable<T>): Promise<Array<T>> {
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const result: T[] = [];
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for await (const it of iterator) {
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result.push(it);
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}
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return result;
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}
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export async function* arrayToAsyncIterator<T>(array: T[]): AsyncGenerator<T, void, void> {
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for (const it of array) {
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yield it;
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}
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}
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export function asyncIteratorToStream<T>(iterator: AsyncGenerator<T, void, void>): ReadableStream<T> {
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return new ReadableStream<T>({
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async pull(controller) {
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const { value, done } = await iterator.next();
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if (done) {
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controller.close();
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} else {
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controller.enqueue(value);
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}
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},
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});
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}
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export function streamPromiseToStream<T>(streamPromise: Promise<ReadableStream<T>>): ReadableStream<T> {
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const transform = new TransformStream({
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async start() {
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const stream = await streamPromise;
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stream.pipeTo(transform.writable).catch(() => {}); // Catch error to avoid unhandled rejection, see https://github.com/nodejs/node/issues/50707
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}
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});
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return transform.readable;
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}
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export function jsonStream(template: any, data: Record<string, AsyncGenerator<any, any, void> | Promise<any> | any | (() => AsyncGenerator<any, any, void> | Promise<any> | any)>): ReadableStream<string> {
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return asyncIteratorToStream((async function*() {
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let lastIndent = '';
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const parts = JSON.stringify(template, undefined, "\t").split(/"%([a-zA-Z0-9-_]+)%"/);
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for (let i = 0; i < parts.length; i++) {
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const part = parts[i];
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if (i % 2 == 0) {
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const lastLineBreak = part.lastIndexOf('\n');
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if (lastLineBreak != -1)
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lastIndent = part.slice(lastLineBreak + 1).match(/^(\t*)/)![1];
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yield part;
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} else {
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const value = await (typeof data[part] === 'function' ? data[part]() : data[part]);
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if (typeof value === 'object' && value && Symbol.asyncIterator in value) {
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let first = true;
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const indent = lastIndent + "\t";
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yield '[\n';
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for await (const obj of value) {
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const prefix = first ? '' : ',\n';
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first = false;
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yield prefix + JSON.stringify(obj, undefined, "\t").replace(/^/gm, indent);
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}
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yield '\n' + lastIndent + ']';
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} else {
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const indent = lastIndent;
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yield JSON.stringify(value, undefined, "\t").replace(/\n/g, '\n' + indent);
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}
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}
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}
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})());
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}
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