take a look at whether that pop-up box is in a form form. You know,

look carefully at the document. There are related methods in the form form

one, reset, that is, data initialization
two, re-create, that is, pop-up window to recreate

official document Portal
one thing to note when using this method is that the data in your form must be standard enough, and the data you need to empty must be in the incoming data Objective.

<el-form :model="data">
    <el-input v-model="aaa"></el-input>
</el-form>

like this, you can only empty the value in data, but the bound aaa cannot be emptied.

// http://json2ts.com/
class FormModel {
  public prop1: string = null;
  public prop2: number = 1;
  public prop3: boolean = true;
  public prop4: number[] = [1];
}

<el-form :model="item">
  <el-form-item>
    <el-input v-model="item.prop1"></el-input>
  </el-form-item>
  <el-form-item>
    <el-input v-model.number="item.prop2"></el-input>
  </el-form-item>
  <el-form-item>
    <el-switch v-model="item.prop3"></el-switch>
  </el-form-item>
</el-form>

methods: {
  init() {
    this.item = new FormItem();
  }
}

I usually use deep copy. Click the pop-up window to determine the assignment