Question

我有一个带有五个计算属性函数的Vue实例，它们对不同的值执行相同的操作。我重复了一遍，我想知道一个更干净的方法，不用重复自己这么多。

在HTML模板中，我有五个输入字段，每个输入字段限制为25个字符，我想显示我显示一个字符计数器：

        <div class='field is-grouped'>
        <p class='control is-expanded'>
            <input 
                class="input" 
                placeholder="Trophy engraving line 1 (25 character limit)" 
                v-model='engraving.line1' 
                v-validate="'required'"
                :class="{'input': true, 'is-danger': errors.has('engraving.line1') }" 
                name='engraving.line1'>
        </p>
        <p class='control'>
            <span>{{ line1count }}</span>
        </p>
    </div>

除了他们说engraving.line2，engraving.line3，engraving.line4和engraving.line5之外，我有五个看起来完全相同的字段。

然后我的组件javascript我定义了雕刻对象，并为每个字段使用相同的计算方法。

export default {
    data(){
        return {
            engraving: {
                line1: '',
                line2: '',
                line3: '',
                line4: '',
                line5: '',
            }
        };
    },
    computed: {
        line1count() {
            var chars = this.engraving.line1.length,
                limit = 25;

            return (limit - chars) + "/" + limit + " characters remaining";
        },
        line2count(){
            var chars = this.engraving.line2.length,
                limit = 25;

            return (limit - chars) + "/" + limit + " characters remaining";
        },
        line3count(){
            var chars = this.engraving.line3.length,
                limit = 25;

            return (limit - chars) + "/" + limit + " characters remaining";
        },
        line4count(){
            var chars = this.engraving.line4.length,
                limit = 25;

            return (limit - chars) + "/" + limit + " characters remaining";
        },
        line5count(){
            var chars = this.engraving.line5.length,
                limit = 25;

            return (limit - chars) + "/" + limit + " characters remaining";
        }
    },

如何重新使用此函数来接受数据参数而不重复自己？

Answer 1

通常对于这种事情，我会做一个小组件。下面的示例删除了验证（只是为了使示例更容易），但就像常规输入元素一样。

使用组件的优点是，您要执行的验证的范围是单个元素，并且可以轻松地重复使用。

＆＃13;

console.clear()

Vue.component("engraving-line",{
  props:["value", "placeholder", "limit"],
  template:`
    <div class='field is-grouped'>
        <p class='control is-expanded'>
            <input 
                class="input" 
                :placeholder="placeholder" 
                v-model='internalValue'>
        </p>
        <p class='control'>
            <span>{{ lineCount }}</span>
        </p>
    </div>
  `,
  computed:{
    internalValue:{
      get() {return this.value},
      set(v) {this.$emit("input", v)}
    },
    lineCount(){
      return `${this.limit - this.value.length}/${this.limit} characters remaining`
    }
  }
})

new Vue({
  el: "#app",
  data:{
    line1: "",
    line2: "",
    line3: "",
    line4: "",
    lineLimit: 25
  }
})

＆＃13;

<script src="https://unpkg.com/vue@2.4.2"></script>
<div id="app">
  <engraving-line :limit="lineLimit" 
                  v-model="line1" 
                  placeholder="Trophy engraving line 1 (25 character limit)">
  </engraving-line>
    <engraving-line :limit="lineLimit" 
                  v-model="line2" 
                  placeholder="Trophy engraving line 2 (25 character limit)">
  </engraving-line>
    <engraving-line :limit="lineLimit" 
                  v-model="line3" 
                  placeholder="Trophy engraving line 3 (25 character limit)">
  </engraving-line>
    <engraving-line :limit="lineLimit" 
                  v-model="line4" 
                  placeholder="Trophy engraving line 4 (25 character limit)">
  </engraving-line>
</div>

＆＃13;

Answer 2

您可以使用方法：

methods: {
    linecount(line, limit) {
        var chars = this.engraving.line[line].length,
        return (limit - chars) + "/" + limit + " characters remaining";
    },
}

然后在你的html中引用它：

<p class='control'>
     <span>{{ linecount(1,25) }}</span>
</p>

如何在Vue计算属性中重用带参数的函数？

2 个答案: