node.js - 单击提交时无法检查空或空

Question

---

点击提交时无法检查是否为空

当按下空格键时，空值将被发送到数据库。

按钮可以将发送的数据提交给数据库

请帮忙。

  <form #Register="ngForm">
  <div style="width: 500px">

    <br/>
    <h4>New Reegister</h4>
    <br/>

    <div class="form-group">
      <dt><label for="name">Name</label></dt>
      <input [(ngModel)]="name" name="name" type="text" class="form-control" placeholder="input your name" data-bv-notempty-message="The name is required" required>
    </div>

    <div class="form-group">
      <dt><label for="lastname">LastName</label></dt>
      <input [(ngModel)]="lastname" name="lastname" type="text" class="form-control" placeholder="input your lastname" data-bv-notempty-message="The lastname is required" required>

    </div>

    <div class="form-group">
      <dt><label for="email2">E-mail</label></dt>
      <input [(ngModel)]="email2" name="email2" type="text" class="form-control" placeholder="input your email" data-bv-notempty-message="email" required [pattern]="emailRegex" >
      <div class= "p-2 text-danger"> <small>* Require Example : xxxxx@gmail.com</small> </div>
    </div>

    <div class="form-group">
      <dt><label for="password2">Password</label></dt>
      <input [(ngModel)]="password2" name="password2" type="password" class="form-control" placeholder="input your password" minlength="4" required>
      <div class= "p-2 text-danger"> <small>* Enter atleast 4 characters</small> </div>
    </div>
  <!--
    <div class="form-group">
        <label for="password3">Password Confirm</label>
        <input [(ngModel)]="password3" name="password3" type="password" class="form-control" placeholder="input your password" required>
    </div>
    -->

    <div class="form-group">
        <dt><label for="passwordhint">Password Hint</label></dt>
        <input [(ngModel)]="passwordhint" name="passwordhint" type="password" class="form-control" placeholder="input your password" minlength="4" required>
        <div class= "p-2 text-danger"> <small>* Enter atleast 4 characters</small> </div>
      </div>

    <button type="submit" type="reset" class="btn btn-danger" [disabled]="!Register.valid" (click)="Regis()">Save</button>
    

  </div>
  </form>

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无法检查数据是否为空

当按下空格键时，空值将被发送到数据库。

按钮可以将发送的数据提交给数据库

请帮忙。

Answer 1

数据“”是有效数据，但它是空的，不是 null。您可以在将其保存到数据库之前通过 trim 函数进行检查。

例如:

let str = ' ';
console.log(str.length) // Length = 1
str = str.trim();
// Here str = '' and you can check length of it
console.log(str.length) // Length = 0

更多详情:trim