Turn a package.json into a browser-ready import map

Install the library:

npm install --save-dev packmap

Now add the following to your package.json:

{
  "scripts": {
    "build": "packmap"
  }
}

And run the following:

npm run build

Packmap will create a browser-ready directory and import map from a package.json file and node_modules. To use it, your packages must meet the following standards:

1. All package.json dependencies must be in-browser dependencies instead of build-time dependencies.
2. There must be only one version of every package. Semantic versioning rules apply.
3. Packages may have directories.lib in their package.json to specify which directory should be made available to the browser.

packmap may be run as a CLI. To see the available options, run the following:

npx packmap --help

# output to build directory
packmap -o build

# specify path to package.json
packmap -p ../my-package/package.json

# specify path to import-map which overrides generated import-map
packmap --override-map ./override-import-map.json

# specify current working directory to base relative urls on.
# In this example, the main package.json will be loaded from subdir, and the
# outputted dist director will also be created inside of subdir.
packmap --cwd ./subdir

Packmap is a node package that is used as follows:

const packmap = require("packmap");

const options = {
  // required
  outdir: "dist",

  // required
  package: "path/to/package.json",

  // optional
  overrideMap: "path/to/override-map.json",

  // optional - defaults to process.cwd()
  cwd: "./subdir",

  // optional - defaults to not logging any packmap info messages.
  // The log function can be used to pipe the logged output of packmap to
  // whatever you'd like it to (stdout, other file, something else).
  log(message) {
    console.log(message);
  }
};

packmap(options)
  .then(() => {
    console.log("done!");
  })
  .catch(err => {
    console.error(err);
  });