Hocus Pocus why does this workus

bot.js

const turn = api.turn();
if (turn === 0) {
    this.generator = (function*() {
        yield* [[3, 8], [2, 16], [3], [0], [1], [0, 27]];
        while (true) {
            yield* [[3, 36], [2, 36], [1, 36], [0, 36]];
            for (let i = 0; i < 20; ++i) {
                yield* [[2, 2], [1]];
            }
            for (let i = 0; i < 20; ++i) {
                yield* [[2, 2], [3]];
            }
            for (let i = 0; i < 20; ++i) {
                yield* [[0, 2], [1]];
            }
            for (let i = 0; i < 20; ++i) {
                yield* [[0, 2], [3]];
            }
            for (let i = 0; i < 10; ++i) {
                yield* [[1], [3, 2]];
                yield* [[2], [0, 2]];
                yield* [[3], [1, 2]];
                yield* [[0], [2, 2]];
            }
        }
    })();

    this.nextCall = 0;
}
if (turn === this.nextCall) {
    const [dir, delay = 1] = this.generator.next().value;
    [api.awayX, api.awayY, api.towardsX, api.towardsY][dir].bind(api)();
    this.nextCall += delay;
}