fileupload.ts

import { Component } from '@angular/core';
import { HttpClient } from '@angular/common/http';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent {

  uploadedImage: String = null;
  uploadedModifiedImage: String = null;

  constructor(private http: HttpClient) {

  }

  fileContent: string = '';
  file: File = null;
  public onChange(fileList: FileList): void {
    this.file = fileList[0];
    let fileReader: FileReader = new FileReader();
    fileReader.onloadend = (x) => {
      this.fileContent = fileReader.result;
      this.http.post('<<your-lamdba-endpoint>>', {'imageName':this.file.name, 'image':this.fileContent}).subscribe((response) => {
        console.log(response);
        this.uploadedModifiedImage = response['modifiedUrl'];
        this.uploadedImage = response['origUrl'];
      })
    }
    fileReader.readAsDataURL(this.file);
  }
}