vue实现上移和下移

1. html

 <el-button size="mini" @click="moveUp(value[index],index)">上移</el-button>
 <el-button size="mini" @click="moveDown(value[index],index)">下移</el-button>

2. js

 moveUp(item, index) {
      if (this.value.length > 1 && index !== 0) {
        var temp = this.value[index - 1];
        this.$set(this.value, index - 1, this.value[index]);
        this.$set(this.value, index, temp);
      }
    },
    moveDown(item, index) {
      if (this.value.length > 1 && index != this.value.length - 1) {
        var temp = this.value[index + 1]; 
        this.$set(this.value, index + 1, this.value[index]);
        this.$set(this.value, index, temp);
      }
    },