stdinBuffer.js

import {parentPort} from "worker_threads"

class StdinBuffer {
    constructor() {
        this.sab = new SharedArrayBuffer(128 * Int32Array.BYTES_PER_ELEMENT)
        this.buffer = new Int32Array(this.sab)
        this.readIndex = 1;
        this.numberOfCharacters = 0;
        this.sentNull = true
    }

    prompt() {
        this.readIndex = 1
        Atomics.store(this.buffer, 0, -1)
        parentPort.postMessage({
            type: 'stdin',
            buffer: this.sab
        })
        Atomics.wait(this.buffer, 0, -1)
        this.numberOfCharacters = this.buffer[0]
    }

    stdin = () => {
        if (this.numberOfCharacters + 1 === this.readIndex) {
            if (!this.sentNull) {
                // Must return null once to indicate we're done for now.
                this.sentNull = true
                return null
            }
            this.sentNull = false
            this.prompt()
        }
        const char = this.buffer[this.readIndex]
        this.readIndex += 1
        // How do I send an EOF??
        return char
    }
}

export default StdinBuffer