Angular 8|9 How to Upload Excel/ Image File using FormData with Post HTTP method

In this tutorial, we will learn How to Upload files like Excel, Image or any document like PDFs to a Web Server in Angular application using FormGroup class and FormData interface.

We are going to create a simple form that will have a file input control to select a file which will be uploaded by clicking on a button.

In Angular, we use the FormData to handle forms that represent the form field controls as we have in a static HTML page.

How to Upload Files in Angular using FormData?

Step 1) Import required modules

To enable a form to upload files to a remote server using the HTTP post method in Angular application, we need to import FormsModule, ReactiveFormsModule and HttpClientModule in the app.module.ts file as shown below:

// app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';

import { AppRoutingModule } from './app-routing.module';
import { AppComponent } from './app.component';

import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { HttpClientModule } from '@angular/common/http';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AppRoutingModule,
    FormsModule,
    ReactiveFormsModule,
    HttpClientModule
  ],
  providers: [],
  bootstrap: [AppComponent]
})
export class AppModule { }

Step 2) Adding a Form in Component Template

Add a simple Form in a component template HTML with [formGroup] and (ngSubmit) event handler. Then add an Input File control and a button to submit the form as shown below:

<h3>Upload File</h3>

<form [formGroup]="fileUploadForm" (ngSubmit)="onFormSubmit()">
    <div class="row">
        <div class="col-sm-12">
            <div>
                <h6 class="head-title margin-top-8"><span>UPLOAD</span></h6>
            </div>
        </div>

        <div class="col-sm-6 text-center">

            <div class="custom-file">
                <input type="file" class="custom-file-input" id="customFile" name="myfile"
                    (change)="onFileSelect($event)" #UploadFileInput>
                <label class="custom-file-label" for="customFile">{{fileInputLabel || 'Choose File'}}</label>
            </div>

        </div>
        <div class="col-sm-6 text-center">
            <button class="btn btn-primary" type="submit">Upload</button>
        </div>
    </div>
</form>

Above we also added a template reference variable #UploadFileInput to reset the input field after file uploaded successfully.

Note: To this form look good, we used bootstrap.css in the index.html file

Step 3) Update Component class file

Next, we will add a reference to the input file control using @ViewChild as ElementRef.

import { Component, OnInit, ViewChild, ElementRef } from '@angular/core';
import { FormGroup, FormBuilder } from '@angular/forms';
import { HttpClient } from '@angular/common/http';
import * as _ from 'lodash';

@Component({
  selector: 'app-uploadfile',
  templateUrl: './uploadfile.component.html',
  styleUrls: ['./uploadfile.component.scss']
})
export class UploadfileComponent implements OnInit {

  @ViewChild('UploadFileInput', { static: false }) uploadFileInput: ElementRef;
  fileUploadForm: FormGroup;
  fileInputLabel: string;

  constructor(
    private http: HttpClient,
    private formBuilder: FormBuilder
  ) { }

  ngOnInit(): void {
    this.fileUploadForm = this.formBuilder.group({
      myfile: ['']
    });
  }

  onFileSelect(event) {
    let af = ['application/vnd.openxmlformats-officedocument.spreadsheetml.sheet', 'application/vnd.ms-excel']
    if (event.target.files.length > 0) {
      const file = event.target.files[0];
      // console.log(file);

      if (!_.includes(af, file.type)) {
        alert('Only EXCEL Docs Allowed!');
      } else {
        this.fileInputLabel = file.name;
        this.fileUploadForm.get('myfile').setValue(file);
      }
    }
  }


  onFormSubmit() {

    if (!this.fileUploadForm.get('myfile').value) {
      alert('Please fill valid details!');
      return false;
    }

    const formData = new FormData();
    formData.append('formFile', this.fileUploadForm.get('myfile').value);
    formData.append('agentId', '007');


    this.http
      .post<any>('http://www.example.com/api/upload', formData).subscribe(response => {
        console.log(response);
        if (response.statusCode === 200) {
          // Reset the file input
          this.uploadFileInput.nativeElement.value = "";
          this.fileInputLabel = undefined;
        }
      }, error => {
        console.log(error);
      });
  }

}