How to fix ERROR Error: Uncaught (in promise): NullInjectorError: StaticInjectorError(AppModule)[HomeComponent -> HttpHeaders]

Question

While fetching from API call using GET method I am facing problem like this

core.js:6014 ERROR Error: Uncaught (in promise): NullInjectorError: StaticInjectorError(AppModule)[HomeComponent -> HttpHeaders]: StaticInjectorError(Platform: core)[HomeComponent -> HttpHeaders]: NullInjectorError: No provider for HttpHeaders! NullInjectorError: StaticInjectorError(AppModule)[HomeComponent -> HttpHeaders]: StaticInjectorError(Platform: core)[HomeComponent -> HttpHeaders]: NullInjectorError: No provider for HttpHeaders! at NullInjector.get (core.js:855) at resolveToken (core.js:17513) at tryResolveToken (core.js:17439) at StaticInjector.get (core.js:17265) at resolveToken (core.js:17513) at tryResolveToken (core.js:17439) at StaticInjector.get (core.js:17265) at resolveNgModuleDep (core.js:30392) at NgModuleRef_.get (core.js:31577) at resolveDep (core.js:32142) at resolvePromise (zone-evergreen.js:797) at resolvePromise (zone-evergreen.js:754) at zone-evergreen.js:858 at ZoneDelegate.invokeTask (zone-evergreen.js:391) at Object.onInvokeTask (core.js:39679) at ZoneDelegate.invokeTask (zone-evergreen.js:390) at Zone.runTask (zone-evergreen.js:168) at drainMicroTaskQueue (zone-evergreen.js:559)

Code:

return this.http
      .get('http://localhost/advanced/frontend/web/leftside-menu/get-left-menu')
      .subscribe(
        (result) => { }
      );

Answer 1

Have you imported HttpClientModule in app.module.ts? if not then put this line code..

import { HttpClientModule } from '@angular/common/http'; 

@NgModule({  
            imports: [ BrowserModule, FormsModule, HttpClientModule ],
            declarations: [ ]
           })