Rewrite Code From Arrow Function To Non Arrow Function

so I want to rewrite this code from an arrow function to a non arrow function, how will this then be done and what will the code be?

Solution 1:

require('isomorphic-fetch');

let items = [];

fetch("https://www.googleapis.com/books/v1/volumes?q=isbn:0747532699")
  .then(function(res) { return res.json(); })
  .then(function (result) {
    items = result.items;
    console.log(items);
  }),
  function (error) {
    console.log(error);
  }