mirror of
https://github.com/vercel-labs/scriptc.git
synced 2026-11-02 07:43:42 +08:00
Chris Tate
0b00ecfc23
`x.constructor` on a value typed as EventEmitter or a stream class stopped at SC2020. The runtime now records each instance's Node class name: fs streams as ReadStream and WriteStream, child process stdio as Socket, worker stdio as ReadableWorkerStdio and WritableWorkerStdio, and Hash/Hmac stream views as Hash and Hmac (zlib streams, the base classes and program subclasses already did). The name is the one Node's leak warning and argument-type errors print, so those messages now name the same class as Node. `x.constructor.name` reads that name (scr_emitter_class_name). `x.constructor === C` for EventEmitter or a stream class tests the instance's own class: C's interval, none of its direct subclasses', and C's name, as fs, zlib, crypto, child process and worker streams share the base classes' vtables. `x.constructor` as a value is the class object of EventEmitter or the stream class the instance belongs to; for instances of the other runtime classes and of program subclasses it reports SC1090 at run time.
49 lines
2.0 KiB
TypeScript
49 lines
2.0 KiB
TypeScript
// x.constructor on instances of EventEmitter and the stream classes:
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// .name is the class Node reports (fs, zlib and program subclasses
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// included), === compares with the instance's own class, and the value
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// is the class object for EventEmitter and the stream classes.
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import { EventEmitter } from "node:events";
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import { Duplex, PassThrough, Readable, Transform, Writable } from "node:stream";
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import * as fs from "node:fs";
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import * as zlib from "node:zlib";
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class Bus extends EventEmitter {}
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const emitter = new EventEmitter();
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const bus: EventEmitter = new Bus();
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console.log("emitter", emitter.constructor === EventEmitter, emitter.constructor.name);
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console.log("subclass", bus.constructor === EventEmitter, bus.constructor.name);
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const streams: Readable[] = [new Readable(), new Duplex(), new Transform(), new PassThrough()];
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for (const s of streams) {
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console.log(
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"stream",
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s.constructor.name,
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s.constructor === Readable,
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s.constructor === Duplex,
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s.constructor === Transform,
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s.constructor === PassThrough,
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s.constructor !== Readable,
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);
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}
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const from = Readable.from(["a"]);
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console.log("from", from.constructor.name, from.constructor === Readable);
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const readStream: Readable = fs.createReadStream(import.meta.filename);
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const writeStream: Writable = fs.createWriteStream("/dev/null");
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console.log("fs", readStream.constructor.name, readStream.constructor === Readable);
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console.log("fs", writeStream.constructor.name, writeStream.constructor === Writable);
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readStream.destroy();
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writeStream.destroy();
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const gzip: Transform = zlib.createGzip();
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const inflate: Transform = zlib.createInflateRaw();
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console.log("zlib", gzip.constructor.name, inflate.constructor.name, gzip.constructor === Transform);
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const kinds: EventEmitter[] = [new EventEmitter(), new Writable(), new PassThrough()];
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for (const k of kinds) {
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const Kind = k.constructor as typeof EventEmitter;
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console.log("value", Kind.name, Kind === EventEmitter, k instanceof Kind, new Kind() instanceof EventEmitter);
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}
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