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When Importing Self Made Vue 3 Library Into Vue 3 Project: “Uncaught TypeError: Cannot read properties of null (reading ‘isCE’)”

I created a custom component library using Vue 3, and after installing it locally thru yarn and registering the components, I kept getting the following error in the browser devtools when using the components in the template:

Uncaught TypeError: Cannot read properties of null (reading ‘isCE’)

Upon researching the issue, it became apparent that the Vue community’s proposed solution isn’t working. I’m running the same Vue 3 version on both projects. I followed the steps to create and modify vue.config.js to alias Vue and disable symlinks, but to no avail.

module.exports = {
  chainWebpack(config) {
    config.resolve.alias.set("vue", path.resolve("./node_modules/vue"));

I followed the rabbit hole which only led to the same conclusions: either modifying vue.config.js worked, or no solution was found. The issue (mainly) seems to be with components with slots.


Try vite instead of vue-cli to create your custom lib. and keep your vue stay at devDependencies in Package.json