Function to a given item to Google Shopping List. Paste the code in the DevTools' console!

add-item-to-google-shopping-list.js

const input = document.getElementsByClassName("listItemInput")[0];
const form = document.getElementsByClassName("addForm")[0];

function addItem(name){
  input.dispatchEvent(new Event("focus"));
  input.value = name;
  input.dispatchEvent(new Event("input"));
  form.dispatchEvent(new Event("submit"));
}