Test cannot read property InnerHTML of null

Question

Trying to run an unit test for the following code: Using Jest and Enzyme for React Js

After inserting a return into a mock function I keep getting the error: Test cannot read property InnerHTML of null

Here is the mock function: const getCleanJSON = jest.fn (() => { return '{}' })

Without the return , I get the following error: Cannot read property 'appendChild' of null. I am probably missing something inside of my mock Function. Any clues ?

const s = document.createElement('script');
  s.id = 'script'
  s.type = 'text/template';
  s.async = true;
  s.innerHTML = script;
  this.instance.appendChild(s);

  this.renderView(serverSideRender);

This is the 2nd method where the error is referring to

renderview() {
 .....
  return (
    engine.parseAndRender( document.getElementById('script').innerHTML, cleanJSON)
     .then( (html) => {
     if(document.getElementById('result')){ 
     document.getElementById('result').innerHTML = html == 'null'? '': html
  }
 }
 )
   .catch(e => document.getElementById('result').innerHTML = pretty(this.escapeHTML(e.stack)))
 )}

Cold Fridge Cold Fridge · Accepted Answer · 2019-03-18T20:07:26

Perhaps return the object directly from the mock function?

const getCleanJSON = jest.fn (() => {} )

Test cannot read property InnerHTML of null

1 Answers