Beginner Exercism • javascript

Robot Simulator

Challenge Overview

Write a robot simulator.

Source: Exercism javascript/robot-simulator

💡 View Solution

export class InvalidDirectionError extends Error {
  constructor() {
    super('Invalid direction');
  }
}

export class Robot {
  constructor() {
    this.bearing = 'north';
    this.coordinates = [0, 0];
  }

  orient(direction) {
    const directions = ['north', 'east', 'south', 'west'];
    if (!directions.includes(direction)) throw new InvalidDirectionError();
    this.bearing = direction;
  }

  turnRight() {
    const map = { north: 'east', east: 'south', south: 'west', west: 'north' };
    this.bearing = map[this.bearing];
  }

  turnLeft() {
    const map = { north: 'west', west: 'south', south: 'east', east: 'north' };
    this.bearing = map[this.bearing];
  }

  advance() {
    if (this.bearing === 'north') this.coordinates[1]++;
    if (this.bearing === 'south') this.coordinates[1]--;
    if (this.bearing === 'east') this.coordinates[0]++;
    if (this.bearing === 'west') this.coordinates[0]--;
  }

  execute(instructions) {
    [...instructions].forEach(instruction => {
      if (instruction === 'L') this.turnLeft();
      if (instruction === 'R') this.turnRight();
      if (instruction === 'A') this.advance();
    });
  }
}