vue cli build with target lib: "require is not defined" when component is imported

Question

I'm trying to export a Vue component as a package, and using vue cli to build the dist. I intend to publish it on npm, but I'm currently using a symbolic link for testing purpose. However even with a simple hello-world project I can't make a valid package.

I created a project:

vue create hello-world

Then I modified the package.json:

  "scripts": {
    "serve": "vue-cli-service serve",
    "build": "vue-cli-service build --target lib --name vue-hello-world ./src/components/HelloWorld.vue",
    "lint": "vue-cli-service lint"
  },
  "main": "./dist/vue-hello-world.common.js",

Then I call

npm run build

and it compiles without error.

Then I make an import in a vue component in another project (I used a symbolic link in node_modules):

import HelloWorld from "hello-world";

On page render I get the following error:

[Vue warn]: Failed to resolve async component: function MediaViewerPdf() {
  return Promise.all(/*! import() */[__webpack_require__.e(62), __webpack_require__.e(46)]).then(__webpack_require__.bind(null, /*! ./viewers/MediaViewerPdf.vue */ "./vuejs/components/mediaViewer/viewers/MediaViewerPdf.vue"));
}
Reason: ReferenceError: require is not defined

Any idea what's happening?

Remarks:

• using vue inspect, I checked that in webpack config that:

target: "web"

• I already set resolve.symlinks at false on the importing project.

EDIT: I have confirmed that it doesn't come from the symbolic link, I have exactly the same error with package directly on node_modules.

Repo with whole code: https://github.com/louis-sanna/vue-hello-world

Answer 1

So I asked the question on the vue-cli repo and I got the solution! https://github.com/vuejs/vue-cli/issues/4245

Turns out NODE_ENV was already set at development in my shell, so it was the mode used to make the build.

Just need to set the mode explicitly and it works:

vue-cli-service build --target lib --name vue-hello-world ./src/components/HelloWorld.vue --mode production

You may need to add it to vue.config.js:

config
  .mode("production")

Answer 2

This happens due to the fact that Vue CLI Webpack setup by default does not import commonjs modules, as described in your "main" field in package.json. So the problem is with the project that attempts import, not with the project that exports the component.

There are two ways to attempt to solve this problem.

1. From the importing project side

You can remedy this by installing babel plugins for the project that imports your components and setting babel.config.js

module.exports = {
  presets: [
    '@vue/app'
  ],
  plugins: [
    '@babel/plugin-transform-modules-commonjs', // leave to import .common.js files
    '@babel/plugin-transform-modules-umd'       // leave to import .umd.js files
  ]
}

But doing this alone will not be sufficient: you also will need to import CSS that is generated with the library by adding this in your entry file

import 'hello-world/dist/vue-hello-world.css';

Note that I have only tested this using yarn link, but I have confidence that this will work with an imported separate npm module just fine.

2. From the library side

The intent (I suppose) of the original question - how do I bundle a library so my users don't have to do this little dance each time they want to use it?

Option 1: don't bundle it - provide .vue files and sources. Just include everything in 'src' directory of your module, write a readme with explanation and be done with it. Let the importing project figure the compilation and bundling out.

Option 2: use rollup with Vue plugin to roll components into bundle. There is an example on how to do that. In that example you can see that your project will be able to import .esm build https://github.com/vuejs/rollup-plugin-vue/tree/master/cookbook/library

Answer 3

Not sure how you are creating the symbolic link, but you should use npm link for that. If you are still having problems (like I did myself) I would suggest you try npm-link-better:

npm install -g npm-link-better
cd vue-hello-world
npm link
cd ../hello-world
nlc -w vue-hello-world

For building component libraries, I suggest you have a look at vue-cli-plugin-component. This plugin already sets up the vue-cli project pretty well.