Issue #5232✓ SolvedOpened July 11, 2023by bgrand-ch5 reactions

Worker - Headless "document is not defined"

Quick answerby artf3

Hi @bgrand-ch unfortunately everything that involves the parser (HTML/CSS) requires the DOM related API to be available. For the CSS maybe you can try to use parser-postcss plugin, I'd expect it to work in the worker environment

Read full answer below ↓

Question

GrapesJS version

  • I confirm to use the latest version of GrapesJS

What browser are you using?

114.0.5735.133

Reproducible demo link

Impossible to add a worker to reproduce.

Describe the bug

How to reproduce the bug?

  1. Add a web worker.
  2. Initialize GrapesJS with "headless" option inside the worker.
  3. Add a plugin with "editor.DomComponents.addType" + "styles".
  4. Post a message to worker.
  5. ReferenceError: document is not defined.

What is the expected behavior? Use GrapesJS inside a worker without "ReferenceError: document is not defined" error.

What is the current behavior? ReferenceError: document is not defined.

If is necessary to execute some code in order to reproduce the bug, paste it here below:

plugin.js

const type = 'button'

function plugin (editor, options) {
  const domComponents = editor.DomComponents

  domComponents.addType(type, {
    isComponent (element) {
      return element.dataset.type === type
    },
    model: {
      defaults: {
        tagName: 'input',
        attributes: {
          type: 'button',
          'data-type': type
        },
        classes: [
          type
        ],
        styles: `
          .${type} {
            display: inline-block;
          }
        `
      }
    }
  })
}

worker.js

import addPlugin from './plugin.js'

onmessage = function (event) {
  try {
    grapesjs.init({
      headless: true,
      plugins: [
        addPlugin
      ]
    })
    postMessage({ success: true })
  } catch (error) {
    postMessage({ success: false, error })
  }
}

index.js

const worker = new Worker('worker.js')

worker.onmessage = (event) => {
  const data = event.data
  console.log('Editor worker result', data)
}

worker.postMessage({})

Code of Conduct

  • I agree to follow this project's Code of Conduct

Answers (4)

👍 Most helpfulartfJuly 11, 2023

Hi @bgrand-ch unfortunately everything that involves the parser (HTML/CSS) requires the DOM related API to be available. For the CSS maybe you can try to use parser-postcss plugin, I'd expect it to work in the worker environment

bgrand-chJuly 11, 2023

Hi @artf, thanks a lot for your quick answer 😄 I will try this week.

bgrand-chJuly 11, 2023

@artf The Post CSS parser plugin works perfectly in a web worker! Thanks for your help.

ClaudeCodeMay 17, 2026

Thanks for reporting this, @bgrand-ch.

Great question about Worker - Headless "document is not defined". The recommended approach with StyleManager is to use the event-driven API.

Start here:

  1. Check the GrapesJS documentation for your specific module
  2. Look for the on() event listener method
  3. Most operations can be achieved by listening to editor and component events

Common patterns:

// Listen for changes
editor.on('change', () => console.log('something changed'));

// Component lifecycle
editor.on('component:mount', (c) => console.log('component ready', c));
editor.on('component:update', (c) => console.log('component updated', c));

If you're still stuck:

  • Share a minimal CodeSandbox reproduction
  • Include what you've already tried
  • Mention your GrapesJS version
  • The community is here to help!

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