How to Implement File Upload in Angular?

Being able to upload the files and use them afterward is the required characteristic of many apps. The following are commonly used elements to perform file upload with Angular.

FormData

FormData is an object that you can use for storing key-value pairs. It allows you to construct an object which aligns with an HTML form. This feature allows you to send the data, such as file upload using the XMLHttpRequest interface or Http client libraries.

You can use the following command to create the FormData:

const formdata = new FormData();

HttpClientModule

HttpClientModule contains an API that you can use to send and fetch the data in your application from the Http servers. You can use the following command to import this module.

Import {HttpClientModule} from ‘@angular/common/http’;

Reactive Forms

Reactive forms allow you to use a model-driven approach to manage form inputs. You can use multiple controls in a form group, validate the form values with the help of these forms. You can use the following to import this module.

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { ReactiveFormsModule } from '@angular/forms';
@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    ReactiveFormsModule
  ],
  providers: [],
  bootstrap: [ AppComponent ]
})
export class AppModule { }

Implement File Upload

Step 1: Install Angular CLI and create a new project

You can install the angular CLI using this command.

npm install -g @angular/cli

You can create a new angular project using the following command.

ng new FileUploadDemo

You can use this command to run the project.

ng serve --open

Read More: Implementation Of Ngx Infinite Scroller Using Angular Application

Step 2: Add the HttpClientModule

You can import this module in the app.module.ts file.

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';
@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    HttpClientModule
  ],
  providers: [],
  bootstrap: [ AppComponent ]
})
export class AppModule { }

Step 3: Create angular components

You can create components using the following command.

After running this command, angular CLI generates four files of this component and added in the declaration array in the app.module.ts file.

Step 4: Adding angular routing

After creating a component, you can add the routing in the app-routing.module.ts file. First, you need to import this component and then add the routes.

import { NgModule } from '@angular/core';
import { Routes, RouterModule } from '@angular/router';
import { AboutComponent } from './about/about.component';
import { HomeComponent } from './home/home.component';
const routes: Routes = [
  { path: '', redirectTo: 'home', pathMatch: 'full' },  
  { path: 'home', component: HomeComponent },  
  { path: 'about', component: AboutComponent },  
];
@NgModule({
  imports: [RouterModule.forRoot(routes)],
  exports: [RouterModule]
})
export class AppRoutingModule { }

Step 5: Setting up angular material

You can use the following command to add angular material.

In the app.module.ts file, you can add the module.

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';
import { HttpClientModule } from '@angular/common/http';
import { HomeComponent } from './home/home.component';
import { AboutComponent } from './about/about.component';
import { BrowserAnimationsModule } from '@angular/platform-browser/animations';
import { MatToolbarModule  } from '@angular/material/toolbar';
import { MatIconModule } from '@angular/material/icon';
import { MatCardModule } from '@angular/material/card';
import { MatButtonModule } from '@angular/material/button';
import { MatProgressBarModule } from '@angular/material/progress-bar';
@NgModule({
  declarations: [
    AppComponent,
    HomeComponent,
    AboutComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    HttpClientModule,
    BrowserAnimationsModule,
    MatToolbarModule,
    MatCardModule,  
    MatButtonModule,  
    MatProgressBarModule,
    MatIconModule
  ],
  providers: [],
  bootstrap: [ AppComponent ]
})
export class AppModule { }

Step 6: Create file upload service

You can use the following command to generate a service.

In the UploadService.ts file, write the following code.

import { Injectable } from '@angular/core';
import { HttpClient, HttpEvent, HttpErrorResponse, HttpEventType } from  '@angular/common/http';  
import { map } from  'rxjs/operators';
@Injectable({
  providedIn: 'root'
})
export class UploadService {
  SERVER_URL: string = "https://file.io/";  
  constructor( private httpClient: HttpClient ) { }
  public upload(formData) {
    return this.httpClient.post<any>(this.SERVER_URL, formData, {  
        reportProgress: true,  
        observe: 'events'  
      });  
  }
}
</any>

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Step 7: After creating the service, you need to define the upload method in the home.component.ts file

import { Component, OnInit, ViewChild, ElementRef  } from '@angular/core';
import { HttpEventType, HttpErrorResponse } from '@angular/common/http';
import { of } from 'rxjs';  
import { catchError, map } from 'rxjs/operators';  
import { UploadService } from  '../upload.service';
@Component({
  selector: 'app-home',
  templateUrl: './home.component.html',
  styleUrls: ['./home.component.scss']
})
export class HomeComponent implements OnInit {
  @ViewChild("fileUpload", {static: false}) fileUpload: ElementRef;files  = [];  
    constructor( private uploadService: UploadService ) { }
  ngOnInit(): void {
  }
  uploadFile(file) {  
    const formData = new FormData();  
    formData.append('file', file.data);  
    file.inProgress = true;  
    this.uploadService.upload(formData).pipe(  
      map(event => {  
        switch (event.type) {  
          case HttpEventType.UploadProgress:  
            file.progress = Math.round(event.loaded * 100 / event.total);  
            break;  
          case HttpEventType.Response:  
            return event;  
        }  
      }),  
      catchError((error: HttpErrorResponse) => {  
        file.inProgress = false;  
        return of(`${file.data.name} upload failed.`);  
      })).subscribe((event: any) => {  
        if (typeof (event) === 'object') {  
          console.log(event.body);  
        }  
      });  
  }
  private uploadFiles() {  
    this.fileUpload.nativeElement.value = '';  
    this.files.forEach(file => {  
      this.uploadFile(file);  
    });  
}
  onClick() {  
    const fileUpload = this.fileUpload.nativeElement;fileUpload.onchange = () => {  
    for ( let index = 0; index < fileUpload.files.length; index++)  
    {  
     const file = fileUpload.files[index];  
     this.files.push({ data: file, inProgress: false, progress: 0});  
    }  
      this.uploadFiles();  
    };  
    fileUpload.click();  
  }
}

Next, you need to create an HTML template. Add the following content in the home.component.html file.

<xmp>
<div>
    <mat-card>  
        <mat-card-content>  
            <ul>  
                <li *ngFor="let file of files">  
                    <mat-progress-bar [value]="file.progress"></mat-progress-bar>  
                    <span id="file-label">  

                    </span>  
                </li>  
            </ul>  
        </mat-card-content>  
        <mat-card-actions>  
            <button mat-button color="warn" (click)="onClick()">  
                <mat-icon>file_upload</mat-icon>  
                Upload  
            </button>  
        </mat-card-actions>  
    </mat-card>
<input type="file" #fileUpload id="fileUpload" name="fileUpload" multiple="multiple" accept="image/*" style="display:none;" />
</div>
</xmp>

Next, add the toolbar in the app.component.html file.

<span id="file-label">
<mat-toolbar color="primary"><mat-progress-bar>  
  <h1>  
    ngImageUpload   
  </h1>  
  <button mat-button="" routerlink=" ">Home  
  </button><button mat-button="" routerlink=" about"></button><button mat-button="" routerlink=" ">About
<router-outlet></router-outlet></button></mat-progress-bar></mat-toolbar></span>

Conclusion

In this blog, we have seen how to perform file upload in angular. We have started the same by installing angular cli and created an angular application. We installed angular material in the angular application.