Encountering a NgForm provider error in Angular 4.4.6 development mode

Question

Encountering a NgForm provider error in Angular 4.4.6 development mode

UPDATE: Identifying the root of the issue has led me to search for a suitable solution.

NOTE: This complication is specific to development mode (not production, and not utilizing AOT).

The "Update" resolution I am implementing can be found here.

In an attempt to resolve an inconsistency with an input in a child component that was failing to update the valid flag on the form, I implemented this solution. Although it functions properly in a basic test project, transferring it to our main project resulted in the following error:

core.es5.js:1020 ERROR Error: Uncaught (in promise): Error: No provider for NgForm!
Error: No provider for NgForm!
    at ZoneAwareError (http://192.168.2.34:4200/vendor.bundle.js:153804:33)
    ...
    at <anonymous> [<root>]

The issue is that the same component may be utilized independently from a form, leading to the absence of a provider for NgForm.

I am currently exploring potential ways to dynamically engage the viewProviders member when a form is not present. Any advice or suggestions would be greatly appreciated!

angular typescript angular-forms

Answer 1

Answer №1

Sure, you have the option to set it as null if there is no parent NgForm provider available:

export function controlContainerFactory(controlContainer?: ControlContainer) {
  return controlContainer;
}

...

viewProviders: [ 
  { 
    provide: ControlContainer, 
    useFactory: controlContainerFactory, 
    deps: [[new Optional(), NgForm]] 
             ^^^^^^^^^^
          this method should work
  } 
]

Check out this Stackblitz example for reference

Answer 2

Sure, you have the option to set it as null if there is no parent NgForm provider available:

export function controlContainerFactory(controlContainer?: ControlContainer) {
  return controlContainer;
}

...

viewProviders: [ 
  { 
    provide: ControlContainer, 
    useFactory: controlContainerFactory, 
    deps: [[new Optional(), NgForm]] 
             ^^^^^^^^^^
          this method should work
  } 
]

Check out this Stackblitz example for reference

Encountering a NgForm provider error in Angular 4.4.6 development mode

Answer №1

Similar questions

When the button is clicked, a fresh row will be added to the table and filled with data

Angular - applying a class to a component's selector

Oops! An unhandled promise error occurred when trying to fetch a URL with a status of 0. The response received has a status code of

Challenges with utilizing Ionic Native in a cross-platform application

Enhance User Experience with Angular Material Autocomplete

What could be causing FormArrayName to consistently display as undefined in my HTML code, even when the safe-navigation operator is employed

What is the best way to retrieve all designs from CouchDB?

Creating an instance of a class using a class decorator, with or without the 'new'

Testing a function in Angular using Karma and Jasmine

Ways to specify an unused parameter within a function

In Angular 4, there are two routes that result in the same endpoint but direct to separate modules

The Angular template-driven form featuring Material inputs will automatically reset itself when initialized

Adding an object to an array in Postgres with TypeORM

What causes old data to linger in component and how to effectively clear it out

Encountering the error message "Angular: invalid URL value sanitization" every time I attempt to refer to a folder within

Checkbox with an indeterminate state in Angular

Is it possible to compile TypeScript modules directly into native code within the JavaScript data file?

Angular 4 allows for dynamically applying the active class to a clicked button, enhancing interactivity

Struggling to access the "this.array" variable within a TypeScript-powered Angular 4 application

The user interface in Angular 7 does not reflect the updated values after subscribing