Client Side Lambda Submission

main.js

function subscribeToList(email) {
  var params = {
      AccountId: "xxxxxxxxxxx", // your AWS user account ID
      RoleArn: "arn:aws:iam::xxxxxxxxxxx:role/Cognito_mailchimpCognitoUnauth_Role", // your Cognito unauth role (it wil look something like this)
      IdentityPoolId: "us-east-1:xxxxxxxxxxxxxxxxx" // the identity pool id found in Cognito
  };
  
  // set the Amazon Cognito region
  AWS.config.region = 'us-east-1';
  // initialize the Credentials object with our parameters
  AWS.config.credentials = new AWS.CognitoIdentityCredentials(params);

  // invoking the actual Lambda function
  var lambda = new AWS.Lambda();
  lambda.invoke({
    FunctionName: 'mailchimpSubscribe', // your function name
    LogType: "Tail",
    InvocationType: "Event",
    Payload: JSON.stringify({
      "email": email
    }) // how you send the email to the Lambda event
  }, function(err, data){
    if (err) { 
      console.log(err, err.stack);
    } else {
      console.log('Thanks! Your signed up to my email list on Mailchimp');
    }
  });
}