Test local npm packages with ease

When working with npm packages, it is good to be able to test it locally without the necessity of publishing it to npm. Here are some ways you can achieve that.

Use npm link

You can create a symlink like this.

In the package:

npm link

In the project that uses the package:

npm link my-package

Now the packages are linked.

To unlink:

npm unlink my-package

Install locally

Install by just referencing the local path inside package.json

{
  "name": "my-project",
  "dependencies": {
    "@myuser/my-package": "file:../lib"
  }
}

And then just install

npm i

Install locally by using npm pack

If you want, you can package the local package and use it locally. Here you are using the same artifact that gets uploaded to npm.

npm pack

This command is generating this file my-package-X-X-X.tgz. Where X.X.X is the semver version.

You can now reference this tarball directly in your main project inside package.json

"dependencies": {
  "@myuser/my-package": "file:../lib/my-package-X-X-X.tgz"
}

Use the package

import "@myuser/my-package/dist/index.css"

Just one example of importing a file from the package.

Bonus: Pre-install a local package with the main project install

Maybe you are developing a package and making a Documentation website for it, or another project that is using lib.

.
├── docs
├── lib

Then you can install the package’s dependencies upon installation in the docs project. Using the preinstall built in npm script, it will install this first upon npm i in he docs project.

"scripts": {
    "preinstall": "npm install ../lib/"
}