babel-plugin-transform-imports

Transforms member style imports:

``

javascript

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

import { merge } from 'lodash';





...into default style imports:

javascript

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

import MyGrid from 'react-bootstrap/lib/Grid';

import merge from 'lodash/merge';





*Note: this plugin is not restricted to the react-bootstrap and lodash

libraries.  You may use it with any library.*



Why?



When Babel encounters a member style import such as:

javascript

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





it will generate something similarish to:

javascript

var reactBootstrap = require('react-bootstrap');

var Grid = reactBootstrap.Grid;

var Row = reactBootstrap.Row;

var Col = reactBootstrap.Col;





Which causes the entire library to be loaded, even though only some components

are needed.  Some libraries are rather large and pulling in the entire module

would cause unnecessary bloat to your client optimized (webpack etc.) bundle.

The only way around this is to use default style imports:

javascript

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:

javascript

import Bootstrap, { Grid } from 'react-bootstrap';

// -- or --

import * as Bootstrap from 'react-bootstrap';





Installation



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





Usage

.babelrc

json

{

  "plugins": [

    ["transform-imports", {

      "react-bootstrap": {

        "transform": "react-bootstrap/lib/${member}",

        "preventFullImport": true

      },

      "lodash": {

        "transform": "lodash/${member}",

        "preventFullImport": true

      }

    }]

  ]

}





Advanced Transformations



$3



Sometimes, you may wish to use regular expressions in your transformation (for

example, to enforce the same convention in all folder levels on the structure

of your library).

.babelrc

json

{

  "plugins": [

    ["transform-imports", {

      "my-library\/?(((\\w)?\/?))": {

        "transform": "my-library/${1}/${member}",

        "preventFullImport": true

      }

    }]

  ]

}





Causes this code:

javascript

import { MyModule } from 'my-library';

import { App } from 'my-library/components';

import { Header, Footer } from 'my-library/components/App';





to become:

javascript

import MyModule from 'my-library/MyModule';

import App from 'my-library/components/App';

import Header from 'my-library/components/App/Header';

import Footer from 'my-library/components/App/Footer';





$3



If you need more advanced or more specific transformation logic, and are using

Babel 7+ with a

babel.config.js

 file, you may provide a function instead of a

string for the

transform

 option:

babel.config.js

javascript

module.exports = {

  presets: ['@babel/env'],

  plugins: [

    ['transform-imports', {

      'my-library': {

        transform: (importName, matches) =>

my-library/etc/${importName.toUpperCase()}

,

        preventFullImport: true,

      },

      'date-fns': {

        transform: importName =>

date-fns/${camelCase(importName)}

,

        preventFullImport: true,

      },

    }]

  ]

};





You may combine a regular expression in the library name with a function

transform, and any captures of the regex will be passed as a second argument.



Webpack



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



webpack.config.js:

javascript

module: {

  rules: [{

    test: /\.js$/,

    exclude: /(node_modules|bower_components)/,

    use: {

      loader: 'babel-loader',

      query: {

        plugins: [

          [require('babel-plugin-transform-imports'), {

            'my-library': {

              transform: function(importName, matches) {

                return 'my-library/etc/' + importName.toUpperCase();

              },

              preventFullImport: true

            }

          }]

        ]

      }

    }

  }]

}





Version 2.0 Breaking Changes



Version 2.0 of this plugin targets Babel 7. Since Babel 7 allows for JS inside

the config via

.babelrc.js or babel.config.js

, the specialized transforms

camelCase, kebabCase, and snakeCase

 have been dropped. If you still need

this functionality, you can import

lodash

 directly in your config file and

use those functions as part of a return value passed to the

transform

 function

(see Using a function as the transformer above).



If you are on Babel 6, this plugin should still work, but if you need the prior

specialized functionality, please use the ^1.0.0 version of this library and

see the documentation located here.



Options



| Name | Type | Required | Default | Description |

| --- | --- | --- | --- | --- |

|

transform | string or function | yes | undefined

 | The library name to use instead of the one specified in the import statement.  ${member} will be replaced with the import name, aka Grid/Row/Col/etc., and ${1-n} will be replaced by any matched regular expression groups. If using a JS Babel config file, a function may be passed directly. (see Advanced Transformations) |

|

preventFullImport | boolean | no | false

 | Whether or not to throw when an import is encountered which would cause the entire module to be imported. |

|

skipDefaultConversion | boolean | no | false | When set to true, will preserve import { X } syntax instead of converting to import X`. |

babel-plugin-transform-imports

Transforms member style imports:

``

javascript

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

import { merge } from 'lodash';





...into default style imports:

javascript

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

import MyGrid from 'react-bootstrap/lib/Grid';

import merge from 'lodash/merge';





*Note: this plugin is not restricted to the react-bootstrap and lodash

libraries.  You may use it with any library.*



Why?



When Babel encounters a member style import such as:

javascript

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





it will generate something similarish to:

javascript

var reactBootstrap = require('react-bootstrap');

var Grid = reactBootstrap.Grid;

var Row = reactBootstrap.Row;

var Col = reactBootstrap.Col;





Which causes the entire library to be loaded, even though only some components

are needed.  Some libraries are rather large and pulling in the entire module

would cause unnecessary bloat to your client optimized (webpack etc.) bundle.

The only way around this is to use default style imports:

javascript

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:

javascript

import Bootstrap, { Grid } from 'react-bootstrap';

// -- or --

import * as Bootstrap from 'react-bootstrap';





Installation



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





Usage

.babelrc

json

{

  "plugins": [

    ["transform-imports", {

      "react-bootstrap": {

        "transform": "react-bootstrap/lib/${member}",

        "preventFullImport": true

      },

      "lodash": {

        "transform": "lodash/${member}",

        "preventFullImport": true

      }

    }]

  ]

}





Advanced Transformations



$3



Sometimes, you may wish to use regular expressions in your transformation (for

example, to enforce the same convention in all folder levels on the structure

of your library).

.babelrc

json

{

  "plugins": [

    ["transform-imports", {

      "my-library\/?(((\\w)?\/?))": {

        "transform": "my-library/${1}/${member}",

        "preventFullImport": true

      }

    }]

  ]

}





Causes this code:

javascript

import { MyModule } from 'my-library';

import { App } from 'my-library/components';

import { Header, Footer } from 'my-library/components/App';





to become:

javascript

import MyModule from 'my-library/MyModule';

import App from 'my-library/components/App';

import Header from 'my-library/components/App/Header';

import Footer from 'my-library/components/App/Footer';





$3



If you need more advanced or more specific transformation logic, and are using

Babel 7+ with a

babel.config.js

 file, you may provide a function instead of a

string for the

transform

 option:

babel.config.js

javascript

module.exports = {

  presets: ['@babel/env'],

  plugins: [

    ['transform-imports', {

      'my-library': {

        transform: (importName, matches) =>

my-library/etc/${importName.toUpperCase()}

,

        preventFullImport: true,

      },

      'date-fns': {

        transform: importName =>

date-fns/${camelCase(importName)}

,

        preventFullImport: true,

      },

    }]

  ]

};





You may combine a regular expression in the library name with a function

transform, and any captures of the regex will be passed as a second argument.



Webpack



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



webpack.config.js:

javascript

module: {

  rules: [{

    test: /\.js$/,

    exclude: /(node_modules|bower_components)/,

    use: {

      loader: 'babel-loader',

      query: {

        plugins: [

          [require('babel-plugin-transform-imports'), {

            'my-library': {

              transform: function(importName, matches) {

                return 'my-library/etc/' + importName.toUpperCase();

              },

              preventFullImport: true

            }

          }]

        ]

      }

    }

  }]

}





Version 2.0 Breaking Changes



Version 2.0 of this plugin targets Babel 7. Since Babel 7 allows for JS inside

the config via

.babelrc.js or babel.config.js

, the specialized transforms

camelCase, kebabCase, and snakeCase

 have been dropped. If you still need

this functionality, you can import

lodash

 directly in your config file and

use those functions as part of a return value passed to the

transform

 function

(see Using a function as the transformer above).



If you are on Babel 6, this plugin should still work, but if you need the prior

specialized functionality, please use the ^1.0.0 version of this library and

see the documentation located here.



Options



| Name | Type | Required | Default | Description |

| --- | --- | --- | --- | --- |

|

transform | string or function | yes | undefined

 | The library name to use instead of the one specified in the import statement.  ${member} will be replaced with the import name, aka Grid/Row/Col/etc., and ${1-n} will be replaced by any matched regular expression groups. If using a JS Babel config file, a function may be passed directly. (see Advanced Transformations) |

|

preventFullImport | boolean | no | false

 | Whether or not to throw when an import is encountered which would cause the entire module to be imported. |

|

skipDefaultConversion | boolean | no | false | When set to true, will preserve import { X } syntax instead of converting to import X`. |