Node.js CLI script to login a Cognito user and print JWT tokens

cognito-login.js

/**
 * Logs the user into the specified Cognito User Pool and prints out JWT tokens
 * @example
 * $ node cognito-login.js username="john.doe" password="j0hn.d0e" user-pool-id="us-east-1_Xxxxxxxx" app-client-id="2axxyyxxyxxxyyxxxyy"
 * {
 *     "accessToken": "eyJra...aQ",
 *     "identityToken": "eyJra...iA",
 *     "refreshToken": "eyJj...Wg"
 * }
 */
const Cognito = require("amazon-cognito-identity-js");

const args = process.argv.slice(2).reduce((acc, arg) => {
  let [k, v = true] = arg.split("=");
  acc[k] = v;
  return acc;
}, {});

const requiredArgs = ["username", "password", "user-pool-id", "app-client-id"];
if (!requiredArgs.every(a => a in args)) {
  console.error(
    `usage: node cognito-login.js username="john.doe" password="j0hn.d0e" user-pool-id="us-east-1_Xxxxxxxx" app-client-id="2axxyyxxyxxxyyxxxyy"`
  );
  console.error("Error: missing arguments");
  return;
}

const authenticationDetails = new Cognito.AuthenticationDetails({
  Username: args.username,
  Password: args.password
});
const userPool = new Cognito.CognitoUserPool({
  UserPoolId: args["user-pool-id"],
  ClientId: args["app-client-id"]
});
const cognitoUser = new Cognito.CognitoUser({
  Username: args.username,
  Pool: userPool
});
cognitoUser.authenticateUser(authenticationDetails, {
  onSuccess: function(result) {
    const object = {
      accessToken: result.getAccessToken().getJwtToken(),
      identityToken: result.getIdToken().getJwtToken(),
      refreshToken: result.getRefreshToken().getToken()
    };
    console.log(JSON.stringify(object, null, 4));
  },

  onFailure: function(err) {
    console.error(err);
  }
});