git clone
npm i
npm run dev

<div class="box">
  <div class="row" v-for="row in list">
    <div class="col" :class="'n-'+col" v-for="col in row">{col}}</div>
  </div>
</div>

_list.forEach(item => {
    let farthest = this.farthestPosition(list, item)
    let next = list[farthest - 1]
    if (next && next === item.value && !_list[farthest - 1].merged) {
      //合并
      list[farthest - 1] = next * 2
      list[item.x] = undefined
      item = {
        x: farthest - 1,
        merged: true,
        value: next * 2
      }
      this.score += next * 2
    } else {
      if (farthest != item.x) {
        list[farthest] = item.value
        list[item.x] = undefined
        item.x = farthest
      }
    }
  })

rotate(arr, n) {
    n = n % 4
    if (n === 0) return arr
    let tmp = Array.from(Array(this.size)).map(() => Array(this.size).fill(undefined))
    for (let i = 0; i < this.size; i++) {
      for (let j = 0; j < this.size; j++) {
        tmp[this.size - 1 - i][j] = arr[j][i]
      }
    }
    if (n > 1) tmp = this.rotate(tmp, n - 1)
    return tmp
  },