[JavaScript知识库]Vue里循环form表单项实例

有的时候我们可能会遇到这种需求，用户点击某个按钮就可以增加一个同样的表单出来，点击一次增加一次。然后要用到深拷贝，Vue.js+ElementUI等等。效果大概如下，就是一个表单有下拉框和两个输入框，现在点击"添加表单"按钮之后就会多一个表单出来，点击"提交表单"后就同时提交两个表单的value值。

代码如下:

<template>
  <div>
    <div style="margin: 10px 0">
      <el-button type="primary" @click="addForm">添加表单</el-button>
      <el-button type="primary" @click="submit">提交表单</el-button>
    </div>
    <div v-for="(item, index) in List" :key="index">
      <el-form ref="form" label-width="80px">
        <el-form-item label="直播平台">
          <el-select
            v-model="item.platform"
            :key="index"
            placeholder="请选择直播平台"
          >
            <el-option
              :label="item2.platformName"
              v-for="(item2, index2) in platformNameList"
              :key="index2"
              :value="item2.platformValue"
            >
            </el-option>
          </el-select>
        </el-form-item>

        <el-form-item label="粉丝量">
          <el-input v-model="item.fanMount" :key="index"></el-input>
        </el-form-item>

        <el-form-item label="平台ID">
          <el-input v-model="item.platformId" :key="index"></el-input>
        </el-form-item>
      </el-form>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      title: "巡查内容页",
      personObj: {
        platform: "",
        fanMount: "",
        platformId: "",
      },
      platformNameList: [
        {
          platformName: "快手",
          platformValue: "1",
        },
        {
          platformName: "抖音",
          platformValue: "2",
        },
        {
          platformName: "淘宝",
          platformValue: "3",
        },
      ],
      List: [
        {
          platform: "",
          fanMount: "",
          platformId: "",
        },
      ],
    };
  },

  methods: {
  //深拷贝
    cloneObj(obj) {
      let ret;
      if (Array.isArray(obj)) {
        //创建一个空数组
        ret = [];
        for (let i = 0; i < obj.length; i++) {
          ret[i] = this.cloneObj(obj[i]);
        }
        return ret;
      } else if (Object.prototype.toString.call(obj) === "[object Object]") {
        ret = {};
        for (let i in obj) {
          ret[i] = this.cloneObj(obj[i]);
        }
        return ret;
      } else {
        return obj;
      }
    },
    //添加表单
    addForm() {
      let arr = this.cloneObj(this.personObj);
      console.log("arr", arr);
      this.List.push(arr);
    },
    //提交表单
    submit() {
      console.log("this.List", this.List);
    },
  },
};
</script>

代码分析:
这里封装了一个深拷贝函数，每次点击添加表单时就会拷贝一份我们定义好的对象，注意这个对象是由我们初始表单的value值组合起来的，我们在最外层用v-for遍历数组List然后每次点击"添加表单"就往数组里push一个对象，最后点击"提交表单"按钮，打印this.List就能看到整个的数组对象了，我们来试一下，选择输入以下值:

控制台打印看下效果:

现在假如说有个需求是，指定添加几项表单，而不是点一次加一次表单，效果如下,有三个按钮，最开始显示一个表单

当我点击"3个"按钮的时候，界面总共有三个表单，如下图：

代码如下:

<template>
  <div>
    <div style="margin: 10px 0">
      <el-button type="primary" @click="add(3)">3个</el-button>
      <el-button type="primary" @click="addForm">添加表单</el-button>
      <el-button type="primary" @click="submit">提交表单</el-button>
    </div>
    <div v-for="(item, index) in List" :key="index">
      <el-form ref="form" label-width="80px">
        <el-form-item label="直播平台">
          <el-select
            v-model="item.platform"
            :key="index"
            placeholder="请选择直播平台"
          >
            <el-option
              :label="item2.platformName"
              v-for="(item2, index2) in platformNameList"
              :key="index2"
              :value="item2.platformValue"
            >
            </el-option>
          </el-select>
        </el-form-item>

        <el-form-item label="粉丝量">
          <el-input v-model="item.fanMount" :key="index"></el-input>
        </el-form-item>

        <el-form-item label="平台ID">
          <el-input v-model="item.platformId" :key="index"></el-input>
        </el-form-item>
      </el-form>
    </div>
  </div>
</template>

<script>
export default {
  data() {
    return {
      title: "巡查内容页",
      personObj: {
        platform: "",
        fanMount: "",
        platformId: "",
      },
      platformNameList: [
        {
          platformName: "快手",
          platformValue: "1",
        },
        {
          platformName: "抖音",
          platformValue: "2",
        },
        {
          platformName: "淘宝",
          platformValue: "3",
        },
      ],
      List: [
        {
          platform: "",

          fanMount: "",
          platformId: "",
        },
      ],
    };
  },

  methods: {
    cloneObj(obj) {
      let ret;
      if (Array.isArray(obj)) {
        //创建一个空数组
        ret = [];
        for (let i = 0; i < obj.length; i++) {
          ret[i] = this.cloneObj(obj[i]);
        }
        return ret;
      } else if (Object.prototype.toString.call(obj) === "[object Object]") {
        ret = {};
        for (let i in obj) {
          ret[i] = this.cloneObj(obj[i]);
        }
        return ret;
      } else {
        return obj;
      }
    },
    add(a) {
      this.addForm(a);
    },
    addForm(a) {
      let arr = this.cloneObj(this.personObj);
      console.log("arr", arr);
      this.List.push(arr);
      a--;
      if (a > 0) {
        this.addForm(a - 1);
      }
    },
    submit() {
      console.log("this.list", this.List);
    },
  },
};
</script>

<style>
</style>

代码分析如下:
点击按钮的add方法的时候传入总共的表单个数，然后在添加表单的方法addForm里用了自减和判断、递归来实现连续点击时的拷贝等。然后我们试一下效果

控制台打印看一下