Advent of Code 2019 day 5 solution (both parts)

methods.js

// @ts-check

const {read} = require("../util/read")

const outputQueue = []
const stdinQueue = []

function dataReceiver(data) {
	const value = +data.toString()
	if (stdinQueue.length) stdinQueue.shift()(value)
}

function listenForInput() {
	process.stdin.on("data", dataReceiver)
}

function stopListeningForInput() {
	process.stdin.removeListener("data", dataReceiver)
}

function waitForInput() {
	return new Promise(resolve => {
		process.stdout.write("input > ")
		stdinQueue.push(resolve)
	})
}

function output(value) {
	console.log(value)
	outputQueue.push(value)
}

const opMap = new Map([
	[1, { // add
		args: 3,
		noTransformArgs: [2],
		code: (tape, value1, value2, loc) => {
			tape[loc] = value1 + value2
			return null
		}
	}],
	[2, { // multiply
		args: 3,
		noTransformArgs: [2],
		code: (tape, value1, value2, loc) => {
			tape[loc] = value1 * value2
			return null
		}
	}],
	[3, { // input
		args: 1,
		noTransformArgs: [0],
		code: (tape, loc) => {
			return waitForInput().then(input => {
				tape[loc] = input
				return null
			})
		}
	}],
	[4, { // output
		args: 1,
		noTransformArgs: [0],
		code: (tape, loc) => {
			output(tape[loc])
			return null
		}
	}],
	[5, { // jump if true
		args: 2,
		noTransformArgs: [],
		code: (tape, condition, loc) => {
			if (condition !== 0) return loc
			else return null
		}
	}],
	[6, { // jump if false
		args: 2,
		noTransformArgs: [],
		code: (tape, condition, loc) => {
			if (condition === 0) return loc
			else return null
		}
	}],
	[7, { // less than
		args: 3,
		noTransformArgs: [2],
		code: (tape, value1, value2, loc) => {
			if (value1 < value2) {
				tape[loc] = 1
			} else {
				tape[loc] = 0
			}
			return null
		}
	}],
	[8, { // equals
		args: 3,
		noTransformArgs: [2],
		code: (tape, value1, value2, loc) => {
			if (value1 === value2) {
				tape[loc] = 1
			} else {
				tape[loc] = 0
			}
			return null
		}
	}],
	[99, { // exit (handled elsewhere)
		args: 0,
		noTransformArgs: [],
		code: () => {
			process.stdin.removeListener("data", dataReceiver)
		}
	}]
])

/**
 * @param {number} pos
 * @param {number[]} tape
 */
async function runInstruction(pos, tape) {
	// quit if broken
	if (tape[pos] === undefined) throw new Error("Out of content!!!")
	// organise
	const inst = tape[pos++]
	console.log("Inst:", inst)
	// organise op
	const opcode = inst % 100
	const op = opMap.get(opcode)
	console.log("Opcode:", opcode)
	const padInst = inst.toString().padStart(2+op.args, "0").slice(0, -2).split("").reverse().join("")
	// organise & resolve params
	let params = []
	for (let i = 0; i < op.args; i++) {
		console.log("next arg:", i, padInst[i], tape[pos])
		if (padInst[i] == "1" || op.noTransformArgs.includes(i)) { // direct
			params.push(tape[pos++])
		} else { // addressed
			params.push(tape[tape[pos++]])
		}
	}
	console.log("Params:", params)
	const newPos = await op.code(tape, ...params)
	if (newPos !== null) pos = newPos
	return {pos, done: opcode === 99}
}

async function runTape(tape) {
	listenForInput()
	let done = false
	let pos = 0
	while (!done) {
		({pos, done} = await runInstruction(pos, tape))
	}
	stopListeningForInput()
	return tape
}

async function runFile(file) {
	let tape = read(file).firstLine().split(",").map(x => +x)
	console.log("Input tape:", tape)
	await runTape(tape)
	console.log("Tape:", tape)
	console.log("Output:", outputQueue)
	const final = outputQueue.length ? ""+outputQueue.slice(-1)[0] : ""
	console.log("Final output:", final)
	return final
}

module.exports.runFile = runFile