Your parameter for the request options in http.put() should actually be of type RequestOptions. Try something like this: let headers = new Headers(); headers.append(‘Content-Type’, ‘application/json’); headers.append(‘authentication’, `${student.token}`); let options = new RequestOptions({ headers: headers }); return this.http .put(url, JSON.stringify(student), options)
update If you use the router you can use lifecycle hooks or resolvers to delay navigation until the data arrived. https://angular.io/guide/router#milestone-5-route-guards To load data before the initial rendering of the root component APP_INITIALIZER can be used How to pass parameters rendered from backend to angular2 bootstrap method original When console.log(this.ev) is executed after this.fetchEvent();, this … Read more
I think that the object you received in your response payload isn’t an array. Perhaps the array you want to iterate is contained into an attribute. You should check the structure of the received data… You could try something like that: getusers() { this.http.get(`https://api.github.com/search/users?q=${this.input1.value}`) .map(response => response.json().items) // <—— .subscribe( data => this.users = data, … Read more
Use the HttpClient class from HttpClientModule if you’re using Angular 4.3.x and above: import { HttpClientModule } from ‘@angular/common/http’; @NgModule({ imports: [ BrowserModule, HttpClientModule ], … class MyService() { constructor(http: HttpClient) {…} It’s an upgraded version of http from @angular/http module with the following improvements: Interceptors allow middleware logic to be inserted into the pipeline … Read more
Since the post method of the Http class returns an observable you need to subscribe it to execute its initialization processing. Observables are lazy. You should have a look at this video for more details: https://egghead.io/lessons/rxjs-rxjs-observables-vs-promises
Angular 2 provides good support for uploading files. No third party library is required. <input type=”file” (change)=”fileChange($event)” placeholder=”Upload file” accept=”.pdf,.doc,.docx”> fileChange(event) { let fileList: FileList = event.target.files; if(fileList.length > 0) { let file: File = fileList[0]; let formData:FormData = new FormData(); formData.append(‘uploadFile’, file, file.name); let headers = new Headers(); /** In Angular 5, including the … Read more
So the answer is no, you don’t. Ng2 will clean it up itself. The Http service source, from Angular’s Http XHR backend source: Notice how it runs the complete() after getting the result. This means it actually unsubscribes on completion. So you don’t need to do it yourself. Here is a test to validate: fetchFilms() … Read more