babel-plugin-transform-modules

babel-plugin-transform-modules

Fork from https://bitbucket.org/amctheatres/babel-transform-imports , and support import style files like babel-plugin-component.

Transforms member style imports:

import { Dialog } from 'cube-ui'

...into default style imports:

import Dialog from 'cube-ui/lib/dialog'

If set style:true config, then it will be transformed to:

import Dialog from 'cube-ui/lib/dialog'
import 'cube-ui/lib/dialog/style.css'

Or set style: "index" config, then it will be transformed to:

import Dialog from 'cube-ui/lib/dialog'
import 'cube-ui/lib/dialog/index.css'

That's stupid, why would you do that?

When Babel encounters a member style import such as:

import { Grid, Row, Col } from 'react-bootstrap';

it will generate something similarish to:

var reactBootstrap = require('react-bootstrap');
var Grid = reactBootstrap.Grid;
var Row = reactBootstrap.Row;
var Col = reactBootstrap.Col;

Some libraries, such as react-bootstrap and lodash, are rather large and pulling in the entire module just to use a few pieces would cause unnecessary bloat to your client optimized (webpack etc.) bundle. The only way around this is to use default style imports:

import Grid from 'react-bootstrap/lib/Grid';
import Row from 'react-bootstrap/lib/Row';
import Col from 'react-bootstrap/lib/Col';

But, the more pieces we need, the more this sucks. This plugin will allow you to pull in just the pieces you need, without a separate import for each item. Additionally, it can be configured to throw when somebody accidentally writes an import which would cause the entire module to resolve, such as:

import Bootstrap, { Grid } from 'react-bootstrap';
// -- or --
import * as Bootstrap from 'react-bootstrap';

Installation

npm install --save-dev babel-plugin-transform-modules

Usage

In .babelrc:

{
    "plugins": [
        ["transform-modules", {
            "cube-ui": {
                "transform": "cube-ui/lib/${member}",
                "preventFullImport": true
            }
        }]
    ]
}

Advanced Transformations

In cases where the provided default string replacement transformation is not sufficient (for example, needing to execute a RegExp on the import name), you may instead provide a path to a .js file which exports a function to run instead. Keep in mind that the .js file will be required relative from this plugin's path, likely located in /node_modules/babel-plugin-transform-modules. You may provide any filename, as long as it ends with .js.

.babelrc:

{
    "plugins": [
        ["transform-modules", {
            "my-library": {
                "transform": "../../path/to/transform.js",
                "preventFullImport": true
            }
        }]
    ]
}

/path/to/transform.js:

module.exports = function(importName, styleName, hasImportName) {
    if (styleName) {
        // set `style: true` option to transform style
        if (!hasImportName && importName === styleName) {
            // full import
            // eg: `import xx from 'my-library'`
            // will be transformed add `require('my-library/etc/style.css')`
            return 'my-library/etc/' + styleName + '.css'
        } else {
            // member import
            // eg: `import {xx} from 'my-library'`
            // will be transformed add `require('my-library/etc/XX/style.css')`
            return 'my-library/etc/' + importName.toUpperCase() + '/' + styleName + '.css'
        }
    }
    return 'my-library/etc/' + importName.toUpperCase();
};

This is a little bit hacky, but options are a bit limited due to .babelrc being a JSON5 file which does not support functions as a type. In Babel 7.0, it appears .babelrc.js files will be supported, at which point this plugin will be updated to allow transform functions directly in the configuration file. See: https://github.com/babel/babel/pull/4892

Webpack

This can be used as a plugin with babel-loader.

webpack.config.js:

module: {
    rules: [
      {
        test: /\.js$/,
        exclude: /(node_modules|bower_components)/,
        use: {
            loader: 'babel-loader',
                query: {
                    plugins: [
                        [require('babel-plugin-transform-modules'), {
                            "my-library": {
                                "transform": function(importName) {
                                    return 'my-library/etc/' + importName.toUpperCase();
                                },
                                preventFullImport: true
                            }
                        }]
                    ]
                }
            }
        }
    ]
}

Options

Name	Type	Required	Default	Description
transform	string	yes	undefined	The library name to use instead of the one specified in the import statement. ${member} will be replaced with the member, aka Grid/Row/Col/etc. Alternatively, pass a path to a .js file which exports a function to process the transform (see Advanced Transformations)
style	boolean,string,object	no	false	Whether or not auto add css style import, if set to true, it will be same as set to 'style'. If set to {name:'sty',ignore:['x', 'y']}, it means all member modules except ['x', 'y'] will be auto add css import with name 'sty.css'
preventFullImport	boolean	no	false	Whether or not to throw when an import is encountered which would cause the entire module to be imported.
camelCase	boolean	no	false	When set to true, runs ${member} through _.camelCase.
kebabCase	boolean	no	false	When set to true, runs ${member} through _.kebabCase.
snakeCase	boolean	no	false	When set to true, runs ${member} through _.snakeCase.
skipDefaultConversion	boolean	no	false	When set to true, will preserve import { X } syntax instead of converting to import X.