初始化一个空的 typescript object，但定义它的属性

Question

I'm practicing Angular-Forms using the template driven approach. I'm aiming to build a UI to contain the result of my data like this:

            <hr>
            <div class="well well-lg">
              <p>Email Address: <span class="bg-info">{{data.email}}</span></p>
              <p>Subscription Type: <span class="bg-info">{{data.sub}}</span></p>
              <p>Password: <span class="bg-info">{{data.pass}}</span></p>
            </div>

So my data object in typescript will take these 3 props as strings I currently have this as the initializer: data: {email: string, sub: string, pass: string};

And in the constructor I have:

this.data.email = '';
this.data.sub = '';
this.data.pass = '';

And on form submit I have:

if(this.myForm.valid){
      this.data.email = this.myForm.value.email;
      this.data.sub = this.myForm.value.subscription;
      this.data.pass = this.myForm.value.password;
      this.myForm.reset();
    }

On reload I'm getting: ERROR TypeError: Cannot set property 'email' of undefined

I'm 99% sure it's because of the way I'm declaring this object. But it seems like I declare it -> give types to it's properties -> give default values in the constructor. But in the constructor this.data is undefined.

What's the typescript way of doing this?

Answer 1

Data is not defined so you can not append properties to the undefined object. Please try this in your constructor:

this.data = {
    email: '',
    sub: '',
    pass: '',
};