Rover.js

class Rover {
    constructor(upperX, upperY) {
            this.upperX = upperX;
            this.upperY = upperY;
            this.N = 1;
            this.E = 2;
            this.S = 3;
            this.W = 4;
            this.x = 0;
            this.y = 0;
            this.facing = this.N;
        }
        //Change the rover position according to passed arguments
    setPosition(x, y, dir) {
        this.x = x;
        this.y = y;
        if (dir == 'N') {
            this.facing = 1;
        } else if (dir == 'E') {
            this.facing = 2;
        } else if (dir == 'S') {
            this.facing = 3;
        } else if (dir == 'W') {
            this.facing = 4;
        }
    }

    //Print the rover's position along with direction
    printPosition() {
        var direction;
        if (this.facing == 1) {
            direction = 'N';
        } else if (this.facing == 2) {
            direction = 'E';
        } else if (this.facing == 3) {
            direction = 'S';
        } else if (this.facing == 4) {
            direction = 'W'
        }
        return (this.x + " " + this.y + " " + direction)
    }
    turnLeft() {
        this.facing = (this.facing - 1) < this.N ? this.W : this.facing - 1;
    }

    turnRight() {
        this.facing = (this.facing + 1) > this.W ? this.N : this.facing + 1;
    }

    move() {
        if (this.facing == this.N) {
            this.y++;
        } else if (this.facing == this.E) {
            this.x++;
        } else if (this.facing == this.S) {
            this.y--;
        } else if (this.facing == this.W) {
            this.x--;
        }
    }
    processRover(commands) {
        for (var idx = 0; idx < commands.length; idx++) {
            this.process1(commands.charAt(idx));
        }
    }
    process1(command) {
        if (command == 'L') {
            this.turnLeft();
        } else if (command == 'R') {
            this.turnRight();
        } else if (command == 'M') {
            this.move();
        } else {
            console.log("Speak in Mars language, please!");
            process.exit();
        }
    }
}
module.exports = Rover;