ionic-s3-uploadfunction.ts

upload(image, imageName, accessToken) {
  return new Promise((resolve, reject) => {
    aws.config.region = this.SYSTEM_VARIABLE.REGION;
    aws.config.credentials = new aws.CognitoIdentityCredentials({
      IdentityPoolId: this.SYSTEM_VARIABLE.COGNITO_IDENTITY.IDENTITY_POOL_ID,
      Logins: {
        "cognito-idp.<REGION_NAME>.amazonaws.com/<USER_POOL_ID>": accessToken
      }
    });

    var s3 = new aws.S3({
      apiVersion: "2006-03-01",
      params: { Bucket: this.SYSTEM_VARIABLE.S3.BUCKET_NAME }
    });

    let buf = new Buffer(image, "base64");

    var data = {
      Bucket: this.SYSTEM_VARIABLE.S3.BUCKET_NAME,
      Key: imageName,
      Body: buf,
      ContentEncoding: "base64",
      ContentType: "image/jpeg"
    };

    s3.putObject(data, (err, res) => {
      if (err) {
        reject(err);
      } else {
        resolve(res);
      }
    });
  });
}