Advent of Code - Day 7

circuit.js

import fetch from 'node-fetch';

const OPERATIONS = {
    'AND': (x, y) => x & y,
    'OR': (x, y) => x | y,
    'NOT': (value) => ~ value,
    'LSHIFT': (x, y) => x << y,
    'RSHIFT': (x, y) => x >> y
}

function parseInput (input) {
  let components = input.split(' ');
  let first;
  let operator;
  let second;

  switch (components.length) {
    case 1:
      return { components: [components] }
    break;
    case 2:
      [operator, first] = components;
      return { components: [first], operation: OPERATIONS[operator] };
    break;
    case 3:
      [first, operator, second] = components;
      return { components: [first, second], operation: OPERATIONS[operator] };
    break;
  }
}

function parseCircuitDefinition (circuitDefinition) {
  return circuitDefinition.split('\n').reduce((circuit, wire) => {
    let [input, output] = wire.split('->').map(string => string.trim());

    circuit[output] = parseInput(input);
    return circuit;
  }, {});
}

function readSignal (circuit, wire, state = {}) {
  let input = circuit[wire];
  let { operation } = input;

  if (state[wire]) {
    return state[wire];
  }

  let components = input.components.map(component => {
    return (!isNaN(component))
      ? parseInt(component)
      : readSignal(circuit, component, state);
  });

  let result = (operation)
    ? operation(...components)
    : components[0];

  return state[wire] = wrap(result, 0, 65536);
}

function wrap (number, min, max) {
  let range = max - min;
  return ((number - min) % range < 0)
    ? number + range
    : number;
}

fetch('https://gist.githubusercontent.com/soutar/60af14354c560946f992/raw/ae38f4a978c2d46578820595e0c77c168934958c/input.txt')
  .then(response => response.text())
  .then(response => {
    let circuit = parseCircuitDefinition(response);
    let signal = readSignal(circuit, 'a');
    console.log(signal);
  });