you really got a hold on me

tractorbeam.js

const fs = require('fs');
const { IntCode, test } = require('../IntCode.js');

class Grid {
  constructor({data, width, height}) {
    if (data) {
      this.data = data;
      this.width = data[0].length;
      this.height = data.length;
    }
    if (width && height) {
      this.width = width;
      this.height = height;
      this.data = [];
      for (let i = 0; i < height; i++) {
        this.data.push(Array(width));
      }
    }
  }
  get(x, y) {
    return this.data[y][x];
  }
  set(x, y, v) {
    this.data[y][x] = v;
  }
  forEach(fn) {
    for (let y = 0; y < this.height; y++) {
      for (let x = 0; x < this.width; x++) {
        let r = fn(x, y, this.get(x, y));
        if (r) return;
      }
    }
  }
  is(x, y, v) {
    return this.get(x, y) === v;
  }
  toString() {
    return this.data.map(row => row.join('')).join('\n');
  }
  static fromString(s) {
    return new Grid(s.split('\n').map(row => row.split('')));
  }
}

async function day19 () { 
  let input = fs.readFileSync(__dirname + '/input.txt').toString('utf8');
  let code = input.split(',').map(n => parseInt(n));

  let g = new Grid({width: 50, height:50});
  let pts = [];
  let count = 0;
  let cpu = new IntCode(code);
  function test(x, y) {
    cpu.reset();
    cpu.input(x, y);
    let o = cpu.run({untilOutput:true});
    return o;
  }
  console.log('performing initial scan');
  // g.forEach((x, y) => g.set(x, y, '.#'[test(x, y)]));
  let found = false;
  let y = 10;
  let x = 0;
  let ls = 0;
  let step = 2000;
  while (!found) {
    while (!test(x, y)) {
      x++;
    }
    let s = 0;
    let ty = y;
    let tx = x;
    while (test(tx, ty)) {
      tx++;
      ty--;
      s++;
    }
    console.log(x, y, tx, ty, step, s);
    if (s === 100 && ls < s && step === 1) {
      found = true;
      console.log(x, ty + 1);
    }
    if (s >= 100) {
      y -= step;
    } else {
      y += step;
    }
    step = Math.ceil(step / 2);
    x = Math.floor(y * .75);
    ls = s;
  }
}

day19().catch(e => console.error(e));