index.js

const extractContent = $ =>
  $('.product')
    .map((_, product) => {
      const $product = $(product);

      return {
        id: $product.find('a[data-product_id]').attr('data-product_id'),
        title: $product.find('h2').text(),
        price: $product.find('.price').text(),
      };
    })
    .toArray();

// ...

const content = extractContent($);
console.log(content);
// [{ id: '759', title: 'Bulbasaur', price: '£63.00' }, ...]