I built a plugin that adds a few custom blocks to guenberg and built a website using gutenberg. Today I wanted to test it with page speed insights and found out that my website has now a lot of render-blocking JS files... All these js files seems to be from gutenberg. My score is 40... What did I do wrong and how can I fix it? I have other websites with my custom blocks and these have 90+ score. Here is the list of render blocking JS files:

  • /wp-includes/js/dist/vendor/lodash.min.js
  • /wp-includes/js/dist/vendor/regenerator-runtime.min.js
  • /wp-includes/js/dist/vendor/wp-polyfill.min.js
  • /wp-includes/js/dist/vendor/react.min.js
  • /wp-includes/js/dist/vendor/react-dom.min.js
  • /wp-includes/js/dist/dom-ready.min.js
  • /wp-includes/js/dist/hooks.min.js
  • /wp-includes/js/dist/i18n.min.js
  • /wp-includes/js/dist/a11y.min.js
  • /wp-includes/js/dist/url.min.js
  • /wp-includes/js/dist/api-fetch.min.js
  • /wp-includes/js/dist/blob.min.js
  • /wp-includes/js/dist/autop.min.js
  • /wp-includes/js/dist/block-serialization-default-parser.min.js
  • /wp-includes/js/dist/deprecated.min.js
  • /wp-includes/js/dist/dom.min.js
  • /wp-includes/js/dist/escape-html.min.js
  • /wp-includes/js/dist/element.min.js
  • /wp-includes/js/dist/is-shallow-equal.min.js
  • /wp-includes/js/dist/keycodes.min.js
  • /wp-includes/js/dist/priority-queue.min.js
  • /wp-includes/js/dist/compose.min.js
  • /wp-includes/js/dist/redux-routine.min.js
  • /wp-includes/js/dist/data.min.js
  • /wp-includes/js/dist/html-entities.min.js
  • /wp-includes/js/dist/shortcode.min.js
  • /wp-includes/js/dist/blocks.min.js
  • /wp-includes/js/dist/vendor/moment.min.js
  • /wp-includes/js/dist/date.min.js
  • /wp-includes/js/dist/primitives.min.js
  • /wp-includes/js/dist/rich-text.min.js
  • /wp-includes/js/dist/warning.min.js
  • /wp-includes/js/dist/components.min.js
  • /wp-includes/js/dist/keyboard-shortcuts.min.js
  • /wp-includes/js/dist/notices.min.js
  • /wp-includes/js/dist/token-list.min.js
  • /wp-includes/js/dist/wordcount.min.js
  • /wp-includes/js/dist/block-editor.min.js
  • /wp-content/plugins/my_plugin/build/blocks/card-block.js
  • /wp-content/plugins/my_plugin/build/blocks/card-row-block.js
  • /wp-content/plugins/my_plugin/build/blocks/special-header-row-block.js
  • Did you do the test logged in? If so, repeat it from a browser where you're just a guest.
    – kero
    Oct 6, 2022 at 12:18
  • @kero google BOT that does the test is not logged as admin on my website.
    – Mateusz
    Oct 6, 2022 at 12:22

1 Answer 1


Ok so...
The problem was caused because I loaded these scripts on the front end in my plugin but these are needed only by editor. To solve this all I had to do was change the content of my block.json files - replace the "script" with "editorScript" so these js files are loaded only for editor :-)


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