I am trying to implement Aes-128-gcm but every time I try to run the code it returns "RangeError: Invalid Key Length"

const crypto = require('crypto'); 
const encryptionKey = crypto.randomBytes(32);
const IV =  crypto.randomBytes(16); 

const data = "who let the dogs out";


var encrypt = ((dataValue) => {
  let cipher = crypto.createCipheriv('aes-128-gcm', encryptionKey, IV);
  let encrypted = cipher.update(dataValue, 'utf8', 'base64');
  encrypted += cipher.final('base64');
  return encrypted;
});

var decrypt = ((encrypted) => {
  let decipher = crypto.createDecipheriv('aes-128-gcm', encryptionKey, IV);
  let decrypted = decipher.update(encrypted, 'base64', 'utf8');
  return (decrypted + decipher.final('utf8'));
});

What have I done wrong?