NodeJs script to get Secrets from secrets manager

secrets.js

class Secrets {
  constructor(awsClient) {
    this.client = awsClient;
  }

  async getSecret(SecretId){
    return new Promise((resolve) => {
      this.client.getSecretValue({ SecretId }, (secretManagerError, data) => {
        if (secretManagerError) {
          if (secretManagerError.code === "DecryptionFailureException")
            throw secretManagerError;
          else if (secretManagerError.code === "InternalServiceErrorException")
            throw secretManagerError;
          else if (secretManagerError.code === "InvalidParameterException")
            throw secretManagerError;
          else if (secretManagerError.code === "InvalidRequestException")
            throw secretManagerError;
          else if (secretManagerError.code === "ResourceNotFoundException")
            throw secretManagerError;
        } else {
          if ("SecretString" in data) {
            let secret = JSON.parse(data.SecretString);
            resolve(secret.TOKEN);
          } else {
            let buff = new Buffer(data.SecretBinary, "base64");
            let decodedBinarySecret = buff.toString("ascii");
            resolve(decodedBinarySecret);
          }
        }
      });
    });
  }
}

module.exports = Secrets;