Angular encountered an ERROR of type TypeError where it cannot access properties that are undefined when trying to read the 'title'

Question

Angular encountered an ERROR of type TypeError where it cannot access properties that are undefined when trying to read the 'title'

I designed a form and I am trying to save the information entered. However, when I attempt to use the save method, an error keeps popping up. How can I troubleshoot this issue and successfully save the data from the form?

angular typescript

Answer 1

Answer №1

My recommendation is to avoid using both formControlName and ngModel on the same input tag. Instead, use formControlName only by assigning a name linked to a FormGroup.

Below is an example of how you can achieve this:

app.component.html

<form [formGroup]="postForm">
    <input type="text" formControlName="title">
    <button (click)="submit()">Save</button>
</form>

app.component.ts

export class AppComponent implements OnInit {
  
  postForm: FormGroup;
  
  constructor(private fb: FormBuilder) { }

  ngOnInit(): void {
    this.createPostForm();
  }

  submit(): void {
    for (const i in this.postForm.controls) {
      this.postForm.controls[i].markAsDirty();
      this.postForm.controls[i].updateValueAndValidity();
    }
    if (this.postForm.valid) {
        // Submit to server... 
    }
  }

  /** Create postform instance */
  createPostForm(): void {
    this.postForm = this.fb.group({
      title: [null, Validators.required],
      content: '',
    
    });
  }

}

In addition, I noticed that you are attempting to check if a post already exists before creating a new one or updating details. My suggestion is to implement this logic on the backend using options like UpdateOrCreate in your database. By passing a post id into your params or body, you can easily determine whether to create a new post or update an existing one. This approach will improve the maintainability of your code.

Answer 2

My recommendation is to avoid using both formControlName and ngModel on the same input tag. Instead, use formControlName only by assigning a name linked to a FormGroup.

Below is an example of how you can achieve this:

app.component.html

<form [formGroup]="postForm">
    <input type="text" formControlName="title">
    <button (click)="submit()">Save</button>
</form>

app.component.ts

export class AppComponent implements OnInit {
  
  postForm: FormGroup;
  
  constructor(private fb: FormBuilder) { }

  ngOnInit(): void {
    this.createPostForm();
  }

  submit(): void {
    for (const i in this.postForm.controls) {
      this.postForm.controls[i].markAsDirty();
      this.postForm.controls[i].updateValueAndValidity();
    }
    if (this.postForm.valid) {
        // Submit to server... 
    }
  }

  /** Create postform instance */
  createPostForm(): void {
    this.postForm = this.fb.group({
      title: [null, Validators.required],
      content: '',
    
    });
  }

}

In addition, I noticed that you are attempting to check if a post already exists before creating a new one or updating details. My suggestion is to implement this logic on the backend using options like UpdateOrCreate in your database. By passing a post id into your params or body, you can easily determine whether to create a new post or update an existing one. This approach will improve the maintainability of your code.

Angular encountered an ERROR of type TypeError where it cannot access properties that are undefined when trying to read the 'title'

Answer №1

Similar questions

Link the ngModel input to an object within an ngFor iteration

The angular-oauth2-oidc library is having issues loading the jsrsasign module

What is the issue with assigning type {intrinsicattributes & true} or type {intrinsicattributes & false} in a React and TypeScript environment?

Signal a return type error when the provided element label does not correspond with an existing entity

Encountering 'null' error in template with Angular 4.1.0 and strictNullChecks mode

Angular FormControl is a built-in class that belongs to the Angular forms module. It

Updating a boolean value when the checkbox is selected

Learning how to effectively incorporate the spread operator with TypeScript's utility type `Parameters` is a valuable skill to

Loading data into the Nuxt store upon application launch

Looking to change the pagination arrow icons in Angular's mat-paginator to something different. Let's replace them with new icons

A helpful guide on integrating a Google font into your Next.js project using Tailwind CSS locally

Step-by-step guide on displaying SVG text on a DOM element using Angular 8

You can easily search and select multiple items from a list using checkboxes with Angular and TypeScript's mat elements

Is it necessary for a TypeScript Library's repository to include the JavaScript version?

TypeORM - Establishing dual Foreign Keys within a single table that point to the identical Primary Key

Challenges encountered while developing Angular FormArrays: Managing value changes, applying validators, and resolving checkbox deselection

Incorporating a JavaScript npm module within a TypeScript webpack application

Router-outlet @input decorator experiencing issues with multiple components

Is KeyValueDiffers within DoCheck limited to working with just a single object per component?

In the latest version of Angular, accessing document.getelementbyid consistently returns null