Is there a better way to compare two objects that have different keys than what I have wrote here?

Question

Basically I'm trying to compare two objects in javascript that have different key names, but I want to match the values of the the objectToSync with the values of the mainObject. Some of the values have different types and some are nested. I tried to use array.reduce method but it quickly turned spaghetti.

But what I have now is this:

// Check data between two objects and return an object
// with only data from the 'mainObject' if it doesn't match  
const categories = [{
  id: 21,
  syncToId: 2
}]

const objectToSync = {
  id: 44,
  status: 'publish',
  name: 'test product',
  price: '1.99000000',
  stock_quantity: 0,
  categories: 21,
  meta_data: [{
    key: 'productid',
    value: '226'
  }, {
    key: 'irrelevant data',
    value: 'meow'
  }]
}

const mainObject = {
  id: 226,
  status: 'ACTIVE',
  name: {
    en: 'Test Product Updated'
  },
  price: 2.99,
  quantity_in_stock: 5,
  group_id: 2,
}


// Use Map?
let check = new Map([
  ['same', (sync, main, type) => {
    const result = sync == main ? undefined : main.type
    return type == 'string' ? String(main) : main
  }],
  ['status', (sync, main) => {
    const status = main == 'ACTIVE' ? 'publish' : 'draft';
    if (sync == status) {
      return
    } else {
      return status
    }
  }]

]);

// if it returns undefined, it means it's still the same and we don't need to change it
const newObject = {
  id: check.get('same')(objectToSync.meta_data.find(x => x.key =='productid').value, mainObject.id),
  name: check.get('same')(objectToSync.name, mainObject.name.en,),
  price: check.get('same')(+objectToSync.price, mainObject.price, 'string'),
  status: check.get('status')(objectToSync.status, mainObject.status),
  // etc
}
// Now Remove 'undefined' values from newObject
Object.keys(newObject).forEach(key => newObject[key] === undefined ? delete newObject[key] : {});

console.log(newObject);

Is there a more practical way of doing this that is easy to read for a beginner like me?

The main reason is because I'm downloading a large data set of products from one API and saving them to a JSON file, then I download my WooCommerce products to a JSON file as well and then compare the API products with my WooCommerce products to make sure they still match. Whatever doesn't I send to WC rest api to update.