Can ngModel be updated in real-time?

Question

Can ngModel be updated in real-time?

I am working with a simple input that has an ngModel attached to it. However, I am unable to see in real-time the content of that ngModel and an error message stating

Cannot read property 'content' of undefined

keeps popping up.

<input ([ngModel])="page.content" />

{{ page.content }}

export interface Page {
  uid: string;
  content: string;
}

@Input() page: Page;

ngOnInit() {
  console.log(this.page.content)
}

I attempted to get a real-time console.log of what I type as I type in the

<input ([ngModel])="page.content" />

You can find a reference on this issue at this stackblitz link

angular typescript

Answer 1

Answer №1

The reason behind this occurrence is due to the Angular lifecycle, where initially the page value is set to null.

To address this in your .html file, you can utilize the following code:

[(ngModel)]="page?.content".

This code ensures that it checks for the existence of the page before accessing its content. Hopefully, this explanation proves helpful!

Answer 2

The reason behind this occurrence is due to the Angular lifecycle, where initially the page value is set to null.

To address this in your .html file, you can utilize the following code:

[(ngModel)]="page?.content".

This code ensures that it checks for the existence of the page before accessing its content. Hopefully, this explanation proves helpful!

Answer 3

Answer №2

Kindly implement the following update in your HTML:

[(ngModel)]="page.content"

instead of

([ngModel])="page.content"

and ensure to initialize the object in your TypeScript file:

this.page = {uid: '000001', content: 'zero'};

Please refer to the modified demo: modified stackblitz

I hope this clarifies any confusion.

Answer 4

Kindly implement the following update in your HTML:

[(ngModel)]="page.content"

instead of

([ngModel])="page.content"

and ensure to initialize the object in your TypeScript file:

this.page = {uid: '000001', content: 'zero'};

Please refer to the modified demo: modified stackblitz

I hope this clarifies any confusion.

Answer 5

Answer №3

Initialize the page object before use. Here is a suggestion:

ngOnInit() {
    this.page = { id: '5678', data: 'world' }
}

or

ngOnInit() {
    this.page = { id: '', data: '' }
}

Best regards

Answer 6

Initialize the page object before use. Here is a suggestion:

ngOnInit() {
    this.page = { id: '5678', data: 'world' }
}

or

ngOnInit() {
    this.page = { id: '', data: '' }
}

Best regards

Can ngModel be updated in real-time?

Answer №1

Answer №2

Answer №3

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