bookmarklet to scrape a html table to json

table2json.js

javascript:
(async () => {
  let parentType = (element,type) => {
    if (element.nodeName.toLowerCase() == type.toLowerCase()) {
      return element;
    } else if (element.parentElement != null) {
      return parentType(element.parentElement,type);
    } else {
      return false;
    }
  };
  let clickInput = (type) => {
    return new Promise((resolve,reject) =>  {
      document.addEventListener("click", (e) => {
        e = parentType(e.target,type);
        if (e) {
          resolve(e);
        }
      });
    });
  };
  let getValue = (cell) => {
    let value = "";
    if (cell.innerText == "") {
      if (cell.querySelector("img") !== null) {
        value = cell.querySelector("img").getAttribute("alt");
      }
    } else {
      value = cell.innerText;
    }
    return value;
  };
  alert("click a table");
  let table = await clickInput("table");
  let tableHead = table.querySelector("tr");
  let attributes = [];
  let output = [];
  [...tableHead.children].map((e,i) => {
    attributes[i] = getValue(e);
  });
  [...table.querySelectorAll("tr")].slice(1).map(row => {
    let rowValues = {};
    [...row.children].map((e,i) => {
      rowValues[attributes[i]] = getValue(e);
    });
    output.push(rowValues);
  });
  alert(JSON.stringify(output))
})();