mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-10-24 06:14:01 +08:00
Chris Tate
794b35a26e
- The forwarding shape — emit(event, ...args) whose rest appears only as super.emit(event, ...args) — lowers per dispatching event as a real hierarchy method, vtable-participating - error events keep the throw-when-unhandled path through overrides; super.emit resolves to the nearest override ancestor, JS's chain - Receivers above every override route through interned instanceOf dispatch; other emitter members and stream-rooted classes keep their fences with reasons stated # Conflicts: # packages/compiler/test/ts7/baselines/order-parity.json
54 lines
1.6 KiB
TypeScript
54 lines
1.6 KiB
TypeScript
// The real-world shape: an emitter subclass as a job queue — constructor
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// args + super(), own fields and methods, colon-spelled event names,
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// multi-argument tuples, once('drain'), listeners registered from outside
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// on a base-typed binding, and removeListener mid-flight.
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import { EventEmitter } from "node:events";
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interface Job {
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id: number;
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name: string;
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}
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class JobQueue extends EventEmitter {
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private jobs: Job[] = [];
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done = 0;
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readonly label: string;
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constructor(label: string) {
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super();
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this.label = label;
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}
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add(name: string): number {
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const job = { id: this.jobs.length + 1, name };
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this.jobs.push(job);
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this.emit("job:added", job.id, name);
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return job.id;
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}
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run(): void {
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for (const job of this.jobs) {
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this.emit("job:done", job.id, job.name, ++this.done);
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}
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this.jobs = [];
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this.emit("drain", this.done);
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}
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}
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const q = new JobQueue("build");
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q.on("job:added", (id: number, name: string) => console.log(`[${q.label}] queued #${id} ${name}`));
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const progress = (id: number, name: string, total: number): void => {
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console.log(`done #${id} ${name} (${total} total)`);
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};
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q.on("job:done", progress);
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q.once("drain", (total: number) => console.log("drained after", total));
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q.add("compile");
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q.add("link");
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q.run();
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// Mid-flight removal: the second batch reports through a fresh listener
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// only; drain's once-listener is already gone.
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q.removeListener("job:done", progress);
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q.on("job:done", (id: number) => console.log("quietly finished", id));
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q.add("package");
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q.run();
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console.log(q.done, q.listenerCount("job:done"), q instanceof JobQueue, q instanceof EventEmitter);
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