This snippet generates a unique code using Math.random(). This code can be used in a referral program

referralProgramGenerateUniqueCode.js

// Import the required libraries - HubSpot NodeJS API client
const hubspot = require('@hubspot/api-client');

exports.main = (event, callback) => {
  
  // Secrets can be accessed via environment variables.
  // Make sure to add your API key under "Secrets" above.
  const hubspotClient = new hubspot.Client({
    apiKey: process.env.HAPIKEY
  });
  
  hubspotClient.crm.contacts.basicApi.getById(event.object.objectId)
    .then(results => {
    
      //Generate random referrer ID using Math.random() and store in variable
      /* 
        IMPORTANT: There is a chance for a duplicate number to occur using Math.random(). this is just intended as an example. 
        Some ways to protect against this would be to use the CRM Search API to check if any other contact already has that ID and 
        if they do generate a new one. Alternatively you could look to create your own unique code using the current date in conjunction with Math.random()
      */
      var referrerID = Math.floor(Math.random() * 1000);
      
      callback({
        outputFields: {
          referrer_id: referrerID //Store the referrerID as a data output field
        }
      });
    })
    .catch(err => {
      console.error(err);
    });
}

Hey @jackcoldrick90 !
Could the code look like this since the return value of the api call is not being used here?

exports.main = (event, callback) => {
    //Generate random referrer ID using Math.random() and store in variable
    /* 
      IMPORTANT: There is a chance for a duplicate number to occur using Math.random(). this is just intended as an example. 
      Some ways to protect against this would be to use the CRM Search API to check if any other contact already has that ID and 
      if they do generate a new one. Alternatively you could look to create your own unique code using the current date in conjunction with Math.random()
    */
    var referrerID = Math.floor(Math.random() * 1000);
    
    callback({
      outputFields: {
        referrer_id: referrerID //Store the referrerID as a data output field
      }
    });
}

Hi @jackcoldrick90. I made a couple of suggestions here

1. Updated to use the Private App in HubSpot
2. Added a function to use not only digits but also characters, making it less chance for duplicate

const hubspot = require('@hubspot/api-client');

function generateRandomCode(length) {
  var result = '';
  var characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
  var charactersLength = characters.length;

  for (var i = 0; i < length; i++) {
    result += characters.charAt(Math.floor(Math.random() * charactersLength));
  }

  return result;
}

exports.main = (event, callback) => {
  
//Rembember to add a secret called "PrivateApp_AccessToken"
const hubspotClient = new hubspot.Client({ accessToken: process.env.PrivateApp_AccessToken });
  hubspotClient.crm.contacts.basicApi.getById(event.object.objectId)
    .then(results => {
    
var referrerID = generateRandomCode(6);
      
      callback({
        outputFields: {
          referrer_id: referrerID //Store the referrerID as a data output field
        }
      });
    })
    .catch(err => {
      console.error(err);
    });
}