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  • vue watch数组或者对象

    1、普通的watch

    data() {
        return {
            frontPoints: 0    
        }
    },
    watch: {
        frontPoints(newValue, oldValue) {
            console.log(newValue)
        }
    }

    2、数组的watch

    data() {
        return {
            winChips: new Array(11).fill(0)   
        }
    },
    watch: {
      winChips: {
        handler(newValue, oldValue) {
          for (let i = 0; i < newValue.length; i++) {
            if (oldValue[i] != newValue[i]) {
              console.log(newValue)
            }
          }
        },
        deep: true
      }
    }

    3、对象的watch

    data() {
      return {
        bet: {
          pokerState: 53,
          pokerHistory: 'local'
        }   
        }
    },
    watch: {
      bet: {
        handler(newValue, oldValue) {
          console.log(newValue)
        },
        deep: true
      }
    }

    tips: 只要bet中的属性发生变化(可被监测到的),便会执行handler函数;如果想监测具体的属性变化,如pokerHistory变化时,才执行handler函数,则可以利用计算属性computed做中间层。事例如下:
    4、对象具体属性的watch[活用computed]

    data() {
      return {
        bet: {
          pokerState: 53,
          pokerHistory: 'local'
        }   
        }
    },
    computed: {
      pokerHistory() {
        return this.bet.pokerHistory
      }
    },
    watch: {
      pokerHistory(newValue, oldValue) {
        console.log(newValue)
      }
    }
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  • 原文地址:https://www.cnblogs.com/kennyliu/p/9573276.html
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