Ionic/Cordova Image Upload to AWS

client.ts

changeAvatar(): void {
    let handler: Function = (source: number) => {
      let updateAvatar: Function = (image_url?: string) => {
        this.api.post('user/avatar', {image_url: image_url})
          .then(
            ()=> {
              this.events.publish('auth:status', true);
              this.updateUserInfo();
            },
            (e)=>console.error(e)
          )
      };
      if(source === -1) return updateAvatar();
      let options: CameraOptions = {
        sourceType: source,
        quality: 100,
        encodingType: 0,
        targetWidth: 500,
        targetHeight: 500,
        correctOrientation: true
      };
      this.platform.ready()
        .then(()=>{
          Camera.getPicture(options)
            .then(
              (picture: any) => {
                console.log(picture);
                Crop.crop(picture, {quality: 100})
                  .then((pic: string)=>{

                    this.api.get('user/signed-url')
                      .then((data: any)=>{
                        let upload_url: string = data.data.upload_url;
                        let image_url: string = data.data.public_url;
                        let transfer = new Transfer();
                        let options: FileUploadOptions = {
                          httpMethod: 'PUT',
                          chunkedMode: false,
                          headers: {
                            'Content-Type': 'image/jpeg'
                          }
                        };
                        transfer.upload(pic, upload_url, options)
                          .then(
                            () => updateAvatar(image_url),
                            (e)=>console.error(e)
                          )
                      }, (error) => console.error(error))

                  });
              },
              (error: any) => console.error(error)
            )
        });
    };

    let select = this.actionSheetCtrl.create({
      title: 'Pick a source',
      buttons: [
        {
          text: 'Camera',
          icon: 'camera',
          handler: () => handler(1)
        },
        {
          text: 'Gallery',
          icon: 'image',
          handler: () => handler(0)
        },
        {
          text: 'Delete avatar',
          icon: 'trash',
          role: 'destructive',
          handler: () => handler(-1)
        },
        {
          text: 'Cancel',
          role: 'cancel',
          icon: 'close'
        }
      ]
    });
    select.present();
  }

server.ts

  static getSignedUrl(req: any, res: any){
    
    // creating new instance of aws.S3 service
    let s3 = new aws.S3();
    
    // here we are setting the path to where the picture should be saved
    let file_name = 'avatars/' + req.auth.user_id + '/' + Date.now() + '.jpg';
    
    // params for the signedURL requestd
    let params = {
      Bucket: 'BUCKET-NAME', // name of the bucket
      Key: file_name, // file path + name
      Expires: 120, // signed URL expires in 120 seconds
      ContentType: 'image/jpeg', // mime type (ideally, we should allow multiple types, and ask the client to send us the type)
      ACL: 'public-read' // this is important so when the image is uploaded, it is accessible to public
    };
    
    s3.getSignedUrl('putObject', params, (err, data) => {
      if(err) console.log(err);
      Utils.res(res, {
        upload_url: data, // this will be the url we upload to
        public_url: 'https://BUCKET-NAME.s3.amazonaws.com/' + file_name // this will be the public url to access the image after upload
      });
    });
  }

This was the only piece of Cordova-S3 releated code that worked for me.
Thanks for sharing.