Angular Formly Form hook OnInit -> field.xxx is possibly undefined

When working with Angular Formly, you may encounter a common error message: “field.xxx is possibly undefined.” This error occurs when you try to access a property of a field object in the OnInit hook, but the field object has not been fully initialized yet. In this blog post, we will explore two solutions to this problem.

Solution 1: Use the ngAfterViewInit hook

One way to avoid the “field.xxx is possibly undefined” error is to move your code from the OnInit hook to the ngAfterViewInit hook. The ngAfterViewInit hook is called after the view has been fully initialized, ensuring that the field object is available.

Here’s an example of how you can implement this solution:

import { Component, OnInit, AfterViewInit } from '@angular/core';

@Component({
  selector: 'app-my-form',
  templateUrl: './my-form.component.html',
  styleUrls: ['./my-form.component.css']
})
export class MyFormComponent implements OnInit, AfterViewInit {

  ngOnInit() {
    // Initialization code
  }

  ngAfterViewInit() {
    // Code that relies on the fully initialized field object
  }

}

Solution 2: Use the safe navigation operator

An alternative solution is to use the safe navigation operator (?.) when accessing properties of the field object. The safe navigation operator allows you to safely access nested properties without throwing an error if any of the intermediate properties are undefined.

Here’s an example of how you can use the safe navigation operator:


  {{ field.xxx }}

By using the safe navigation operator, you can prevent the “field.xxx is possibly undefined” error from occurring.

These are two possible solutions to the “Angular Formly Form hook OnInit -> field.xxx is possibly undefined” problem. Choose the solution that best fits your needs and implement it in your code to resolve the issue.

Feel free to leave a comment if you have any questions or other solutions to share!

Final Output: