babel-plugin-bare-import-rewrite

Babel plugin to rewrite bare imports. In theory this will become obsolete if/when browsers get support for import maps. See domenic/package-name-maps for information about the proposal.

Install babel-plugin-bare-import-rewrite

This module requires node.js 8 or above and @babel/core.

npm i babel-plugin-bare-import-rewrite

Usage

Add bare-import-rewrite to plugins in your babel settings.

Settings

{
    "plugins": [
        ["bare-import-rewrite", {
            "modulesDir": "/node_modules",
            "rootBaseDir": ".",
            "alwaysRootImport": []
        }]
    ]
}

If the plugin settings object is omitted the defaults are used:

{
    "plugins": ["bare-import-rewrite"]
}

modulesDir

The URL path in which node_modules will be published on the web server. This must always be an absolute directory without hostname. Default "/node_modules".

rootBaseDir

The project base directory. This should contain the package.json and node_modules of the application. Default process.cwd().

alwaysRootImport

This contains a list of module bare names which should always be forced to import from the root node_modules. ['**'] can be used to specify that all modules should be resolved from the root folder. No attempt is made to verify that overridden modules are compatible. Each element is used as a pattern to be processed with minimatch. Default [].

neverRootImport

This contains a list of module bare names which should never be forced to imported from the root node_modules. Processed with minimatch. Default [].

This example will force all modules to be loaded from the root node_modules except for some-exception:

{
    "alwaysRootImport": ["**"],
    "neverRootImport": ["some-exception"]
}

extensions

A list of extensions to use in resolver. Default ['.mjs', '.js', '.json'].

.resolve(importModule, sourceFileName, pluginOptions) - Resolve absolute path.

This function is used internally by the babel plugin, is exposed so it can be used by analyzers to build a list of scripts being imported. The pluginOptions argument takes the same values as the babel plugin and uses the same defaults.

const {resolve} = require('babel-plugin-bare-import-rewrite');

const importModule = '@polymer/lit-element';
const pluginOptions = {
    "alwaysRootImport": ["@polymer/*"],
};
try {
    const absPath = resolve(importModule, __filename, pluginOptions);
    console.log(`The requested module ${importModule} is in ${absPath}.`);
} catch (e) {
    console.error(`Cound not resolve ${importModule}:`, e);
}

Running tests

Tests are provided by xo and ava.

npm install
npm test

Attribution

This module is based on code found in polymer-build and polymer-analyzer.