var _ = require("lodash/fp");
let game = [[2, 2, 0, 0], [4, 0, 4, 0], [8, 0, 0, 8], [16, 16, 0, 0]]; // Sample state
let slide = _.flow(
_.reduceRight(
(v, acc) =>
v === 0 ? [_.concat(acc[0], v), acc[1]] : [acc[0], _.concat(v, acc[1])],
[[], []]
),
_.flatten
);
let merge = _.flow(
_.reduceRight(
(v, acc) => {
acc[0].unshift(v);
if (acc[0].length === 2) {
if (acc[0][0] === acc[0][1]) {
acc[1] = _.concat(0, _.concat(acc[0][0] + acc[0][1], acc[1]));
acc[0] = [];
} else {
acc[1] = _.concat(acc[0].pop(), acc[1]);
}
}
return acc;
},
[[], []]
),
_.flatten
);
let take = arr => arr.slice(0,4);
// Moves one line
let moveLine = _.flow(
slide,
merge,
take
);
// Moves the 4 lines
let moveBoard = _.map(moveLine)
console.log(moveBoard(game));
