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How to implement the number input box component in Vue

亚连
亚连Original
2018-06-19 17:23:351950browse

This article introduces to you the development of numerical input box components based on Vue through example code. Friends who need it can refer to it

As Vue becomes more and more popular, there are many related component libraries. Only wheels are used. No matter how hard it is, we still have to build it!!!

1. Overview

API for Vue component development: props, events and slots

2. Component code

github address: https://github.com/MengFangui/VueInputNumber

Effect:

(1)index.html

<!DOCTYPE html>
<html lang="zh">
  <head>
    <meta charset="UTF-8" />
    <title>数字输入框组件</title>
  </head>
  <body>
    <p id="app">
      <!--数字输入框组件命名为:input-number-->
      <!--数字输入框组件默认值为5,最大值为10,最小值为0-->
      <input-number v-model=&#39;value&#39; :max=&#39;10&#39; :min=&#39;0&#39;></input-number>
    </p>
    <script src="https://cdn.bootcss.com/vue/2.5.9/vue.min.js"></script>
    <script src="js/input-number.js" type="text/javascript" charset="utf-8"></script>
    <script src="js/index.js" type="text/javascript" charset="utf-8"></script>
  </body>
</html>

(2)input-number.js

//验证输入值是否为数字
function isValueNumber(value) {
  return(/(^-?[0-9]+\.{1}\d+$)|(^-?[1-9]*$)|(^-?0{1}$)/).test(value + &#39;&#39;);
}
Vue.component(&#39;input-number&#39;, {
  //模板
  template: `
  <p class="input-number">
      <input type="text" :value="currentValue" @change="handleChange" />
    <button @click="handleDown" :disabled="currentValue <= min">-</button>
    <button @click="handleUp" :disabled="currentValue >= max">+</button>
  </p>
  `,
  //props实现与父组件的通信(父组件-->子组件)
  //对每个props进行校验,props的值可以是数组,也可以是对象
  props: {
    max: {
      //必须是数字类型
      type: Number,
      //默认值为Infinity
      default: Infinity
    },
    min: {
      type: Number,
      default: -Infinity
    },
    value: {
      type: Number,
      default: 0
    }
  },
  //Vue组件为单向数据流,声明data来引用父组件的value,在组件内部维护currentValue
  data: function() {
    return {
      currentValue: this.value
    }
  },
  //监听:与父组件通信 (子组件-->父组件)
  watch: {
    currentValue: function(val) {
      //使用v-model改变value 
      //this指向当前组件实例
      this.$emit(&#39;input&#39;, val)
    }
    //    ,
    //本示例未使用自定义函数,使用了v-mode input函数来更新value
    //    value: function(val) {
    //      //自定义事件on-change,告知父组件数字输入框值有所改变
    //      this.$emit(&#39;on-change&#39;, val)
    //    }
  },
  methods: {
    //父组件传递过来的值可能不符合条件(大于最大值,小于最小值)
    updateValue: function(val) {
      if(val > this.max) {
        val = this.max;
      }
      if(val < this.min) {
        val = this.min;
      }
      this.currentValue = val;
    },
    handleDown: function() {
      if(this.currentValue <= this.min) {
        return;
      }
      this.currentValue -= 1;
    },
    handleUp: function() {
      if(this.currentValue >= this.max) {
        return;
      }
      this.currentValue += 1;
    },
    handleChange: function(event) {
      var val = event.target.value.trim();
      var max = this.max;
      var min = this.min;
      if(isValueNumber(val)) {
        val = Number(val);
        this.currentValue = val;
        if(val > max) {
          this.current = max;
        }
        if(val < min) {
          this.current = min;
        }
      } else {
        //如果输入的不是数字,将输入的内容重置为之前的currentValue
        event.target.value = this.currentValue;
      }
    }
  },
  //初始化
  mounted: function() {
    this.updateValue(this.value);
  }
})

(3)index.js

var app = new Vue({
  el: &#39;#app&#39;,
  data: {
    //数字输入框组件默认值为5(父组件设置初始化值)
    value: 5
  }
})

The above is what I compiled for everyone. I hope it will be helpful to everyone in the future.

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