src/day02.js

const input = `RRLUDDLDUDUDUDRDDDRDDRLUUUDRUDURURURLRDDULLLDRRRRULDDRDDURDLURLURRUULRURDDDDLDDRRLDUDUUDURURDLDRRURDLLLDLLRUDRLDDRUULLLLLRRLDUDLUUDRUULLRLLLRLUURDLDLLDDRULDLUURRURLUUURLLDDULRDULULRULDDLRDDUUDLRRURLLURURLDDLURRLUURRRRLDRDLDUDRUDDRULLDUDDLRRLUUUUUDDLLDRLURDDRLLUDULDRDDLLUURUUUURDRLRLLULUULULLRRDLULRUDURDLRLRDDDRULLUULRURULLLUDUURUUUURUULDURDRRRULRLULDLRRULULUUDDDRDURLLURLLDUUUUDULRDLRDUUDDLDUDRLLRLRRRLULUDDDURLRRURUDDDRDRDRLLRDRDLDDRRDRDLLRLLLRRULRDDURRDUDRURDLDULLRRLURLRLLDURRRLLDRRURRRUULDRLDUULRDLDLURUDLLDLLUUDDDUUUDRL
DLRRDRRDDRRDURLUDDDDDULDDLLDRLURDDDDDDRDDDRDDDLLRRULLLRUDULLDURULRRDLURURUDRUURDRLUURRUDRUULUURULULDDLLDDRLDUDDRDRDDUULDULDDLUDUDDUDLULLUDLLLLLRRRUURLUUUULRURULUDDULLLRLRDRUUULULRUUUULRDLLDLDRDRDRDRRUUURULDUUDLDRDRURRUDDRLDULDDRULRRRLRDDUUDRUDLDULDURRDUDDLULULLDULLLRRRDULLLRRURDUURULDRDURRURRRRDLDRRUDDLLLDRDRDRURLUURURRUUURRUDLDDULDRDRRURDLUULDDUUUURLRUULRUURLUUUDLUDRLURUDLDLDLURUURLDURDDDDRURULLULLDRDLLRRLDLRRRDURDULLLDLRLDR
URURLLDRDLULULRDRRDDUUUDDRDUURULLULDRLUDLRUDDDLDRRLURLURUUDRLDUULDRDURRLLUDLDURRRRLURLDDRULRLDULDDRRLURDDRLUDDULUDULRLDULDLDUDRLLDDRRRDULLDLRRLDRLURLUULDDDDURULLDLLLDRRLRRLLRDDRDLDRURRUURLLDDDLRRRRRDLRRDRLDDDLULULRLUURULURUUDRULRLLRDLDULDRLLLDLRRRUDURLUURRUDURLDDDRDRURURRLRRLDDRURULDRUURRLULDLUDUULDLUULUDURRDDRLLLRLRRLUUURRDRUULLLRUUURLLDDRDRULDULURRDRURLRRLRDURRURRDLDUDRURUULULDDUDUULDRDURRRDLURRLRLDUDRDULLURLRRUDLUDRRRULRURDUDDDURLRULRRUDUUDDLLLURLLRLLDRDUURDDLUDLURDRRDLLRLURRUURRLDUUUUDUD
DRRDRRRLDDLDUDRDLRUUDRDUDRRDUDRDURRDDRLLURUUDRLRDDULLUULRUUDDRLDLRULDLRLDUDULUULLLRDLURDRDURURDUDUDDDRRLRRLLRULLLLRDRDLRRDDDLULDLLUUULRDURRULDDUDDDURRDRDRDRULRRRDRUDLLDDDRULRRLUDRDLDLDDDLRLRLRLDULRLLRLRDUUULLRRDLLRDULURRLDUDDULDDRLUDLULLRLDUDLULRDURLRULLRRDRDDLUULUUUULDRLLDRDLUDURRLLDURLLDDLLUULLDURULULDLUUDLRURRRULUDRLDRDURLDUDDULRDRRDDRLRRDDRUDRURULDRRLUURUDULDDDLRRRRDRRRLLURUURLRLULUULLRLRDLRRLLUULLDURDLULURDLRUUDUUURURUURDDRLULUUULRDRDRUUDDDRDRL
RLRUDDUUDDDDRRLRUUDLLDRUUUDRRDLDRLRLLDRLUDDURDLDUDRRUURULLRRLUULLUDRDRUDDULRLLUDLULRLRRUUDLDLRDDDRDDDUDLULDLRRLUDUDDRRRRDRDRUUDDURLRDLLDLDLRRDURULDRLRRURULRDDLLLRULLRUUUDLDUURDUUDDRRRDDRLDDRULRRRDRRLUDDDRUURRDRRDURDRUDRRDLUDDURRLUDUDLLRUURLRLLLDDURUDLDRLRLLDLLULLDRULUURLDDULDDRDDDURULLDRDDLURRDDRRRLDLRLRRLLDLLLRDUDDULRLUDDUULUDLDDDULULDLRDDLDLLLDUUDLRRLRDRRUUUURLDLRRLDULURLDRDURDDRURLDLDULURRRLRUDLDURDLLUDULDDU`;

const inputDemo = `ULL
RRDDD
LURDL
UUUUD`;

const layout1 = [
    1, 2, 3,
    4, 5, 6,
    7, 8, 9
]


const layout2 = [
    0,0,1,0,0,
    0,2,3,4,0,
    5,6,7,8,9,
    0,10,11,12,0,
    0,0,13,0,0,
]

export class Numpad{
    constructor(width, height, startRow = 0, startColumn = 0, keyLayout){
        this.keyLayout = keyLayout;
        this.keys = [];
        this.rows = width;
        this.columns = height;
        this.currentRow = startRow;
        this.currentColumn = startColumn;
    }
    
    get value(){
        return this.keyLayout[this.index].toString(16);
    }
    
    get index(){
        return this.currentRow * this.rows + this.currentColumn;
    }
    
    move({columns, rows}) {
        if(this.canMove(columns, rows)){
            this.currentColumn = this.currentColumn + columns;
            this.currentRow = this.currentRow + rows;
            
            return this.index;
        }
        return false;
    }
    
    canMove(columns = 0, rows = 0) {
        let newIndex = (this.currentRow + rows) * this.columns + (this.currentColumn + columns);
        return this.keyLayout[newIndex] > 0 && this.inBounds(columns, rows);
        
       
    }
    
    inBounds(columns, rows){
        return (this.currentRow + rows) < this.rows &&
            (this.currentRow + rows) >= 0 &&
            (this.currentColumn + columns) < this.columns &&
            (this.currentColumn + columns) >= 0;
    }
    saveKey(){
        this.keys.push(this.value);
    }
    
    getCombination(){
        return this.keys.join('-').toUpperCase();
    }
    
}

const DIRECTIONS = {
    'U': {columns: 0, rows: -1, name: 'UP'},
    'D': {columns: 0, rows: 1, name: 'DOWN'},
    'L': {columns: -1, rows: 0, name: 'LEFT'},
    'R': {columns: 1, rows: 0, name: 'RIGHT'}
}

export function run(){

    let numpad = new Numpad(3, 3, 1, 1, layout1);
    //numpad = new Numpad(5, 5, 2, 0, layout2);
    
    let commandsPerKey = inputDemo.split('\n');
    commandsPerKey = input.split('\n');
    
    commandsPerKey.forEach(keyTokens => {
        let commands = keyTokens.split('');
        commands.forEach(token => {
            let direction = DIRECTIONS[token];
            numpad.move(direction);
        });
        
        numpad.saveKey();
    });
    
    console.log(numpad.getCombination());
    
}