Solving ‘error In :0:0 Caused By: No Provider For’ In Angular

Understanding ‘error In :0:0 Caused By: No Provider For’ in Angular

In Angular, this error occurs when a component or service attempts to inject a dependency that is not registered in the module’s provider list. This typically happens when you try to use a service or component in a template or component without properly importing and providing the necessary module.

Resolving the Issue

To resolve this issue, ensure that the module providing the missing dependency is properly imported and that the dependency is registered as a provider in the module’s providers array. The following steps explain how to do this:

1. Import the Module: Import the module that provides the missing dependency into your module. For example, if your module needs the ProductService, make sure to import the ProductServiceModule in your module’s declaration list.

import { ProductServiceModule } from './product-service.module';

@NgModule({
  imports: [ProductServiceModule]
  ...
})
export class AppModule { }

2. Add Provider: Register the missing dependency as a provider in the providers array of your module.
   • For services, use the provide and useClass properties.
   • For components and directives, use the provide and useValue properties.

@NgModule({
  ...
  providers: [
    { provide: ProductService, useClass: ProductServiceImpl }
  ]
})
export class AppModule { }

3. Restart your Application: After making these changes, restart your Angular application. The missing dependency should now be injected properly and the error should disappear.

Example

Consider the following example:

Component:

import { Component } from '@angular/core';
import { ProductService } from './product.service';

@Component({
  selector: 'my-component',
  template: `<div>{{ProductService.getProduct()}}</div>`,
})
export class MyComponent { }

Module:

import { NgModule } from '@angular/core';
import { MyComponent } from './my-component';

@NgModule({
  declarations: [MyComponent],
})
export class MyModule { }

In this example, the ProductService is not provided in the MyModule. Therefore, when the MyComponent attempts to inject the ProductService, it throws the ‘error In :0:0 Caused By: No Provider For’ error. To fix this error, import the ProductServiceModule into MyModule and add its provider to the providers array.