智能网关-babel-plugin-root-import-PROSAGA-码农传奇

Babel plugin to add the opportunity to use import and require with root based
paths.

Example

// Without this plugin...
import SomeExample from '../../../some/example.js';
const OtherExample = require('../../../other/example.js');
import('../../../other/dynamic').then((mod) => {
  // ...
});
// With babel-plugin-root-import you can write...
import SomeExample from '~/some/example.js';
const OtherExample = require('~/other/example.js');
import('~/other/dynamic').then((mod) => {
  // ...
});

Install

Install with your package manager of choice.

npm install babel-plugin-root-import --save-dev

yarn add babel-plugin-root-import --dev

Use

Add it to your plugins array in your babel config, e.g. a .babelrc file.

{
  "plugins": [
    ["babel-plugin-root-import"]
  ]
}

For recent react-native versions, add it as a plugin in babel.config.js:

module.exports = (api) => {
  api.cache(true);
  return {
    plugins: ['babel-plugin-root-import'],
  };
};

For the rest of this readme, it’s implied that you’ll configure the plugin as above
when using react-native.

Config

You can configure this plugin by changing the string plugin name to a two-item array.
Note that this array is nested inside the plugins array. Here’s an example with the
default config.

  "plugins": [
    [
      "babel-plugin-root-import",
      {
        "rootPathSuffix": "./",
        "rootPathPrefix": "~/"
      }
    ]
  ],

Multiple rules may be specified by creating an object with
{ "paths": [firstItem, secondItem] }, e.g.

  "plugins": [
    [
      "babel-plugin-root-import",
      {
        "paths": [
          {
            "rootPathSuffix": "./src/components",
            "rootPathPrefix": "~/"
          },
          {
            "rootPathSuffix": "./src/utils",
            "rootPathPrefix": "!/"
          },
        ]
      }
    ]
  ],

Custom rootPathSuffix

By default, the import will be relative to the working directory of the process
running babel. Typically this means you’ll have import paths like ~/src/foo.js. You
can change the prefix of "./" to e.g. "src" or "src/js" with this config option.

{
  "plugins": [
    ["babel-plugin-root-import", {
      "rootPathSuffix": "src/js"
    }]
  ]
}

The paths "src/js" and "./src/js" behave the same.

Custom rootPathPrefix

If you don’t like the ~ syntax you can use your own symbol (for example an #
symbol or \ or anything you want). Using @ is not recommended as NPM allows @ in
package names. ~ is the default since it’s very unlikely to conflict with anything
(and wouldn’t be expanded to HOME anyway).

{
  "plugins": [
    ["babel-plugin-root-import", {
      "rootPathPrefix": "#/"
    }]
  ]
}
// Now you can use the plugin like this
import foo from '#/my-file';

If you set it to e.g. "#/" then it’ll require the slash in the import path.

Custom root

By default everything is resolved relative to the current working directory. You can
change this with the root config option. To use it effectively, you’ll need to
configure babel with one of the JavaScript config file variants, rather than JSON.

For example, the following .babelrc.js file causes imports to resolve relative to
the directory .babelrc.js is in.

const rootImportOpts = {
  root: __dirname,
  rootPathPrefix: '~/',
  rootPathSuffix: 'src/js',
};
module.exports = {
  plugins: [['babel-plugin-root-import', rootImportOpts]],
};

babel.config.js

js
const rootImportOpts = {
  root: __dirname,
  rootPathPrefix: '~/',
  rootPathSuffix: 'src/js',
};

module.exports = (api) => {
  api.cache(true);

  const plugins = [['babel-plugin-root-import', rootImportOpts]];

  return { plugins };
};

Function root variant

This .babelrc.js aliases @/foo to ./internals/foo.js since it’s always relative
to the file doing the import (contrived example).

js
const rootImportOpts = {
  root: (sourcePath) => path.dirname(sourcePath),
  rootPathPrefix: '@/',
  rootPathSuffix: 'internals',
};

module.exports = {
  plugins: [['babel-plugin-root-import', rootImportOpts]],
};

Transform paths for custom functions

If you have the need to transform paths also for other function calls you can
configure them. But please be aware that this is kind of error prone because custom
function names in Javascript are not static and can differ.

{
  "plugins": [
    ["babel-plugin-root-import", {
      "functions": ["jest.mock"]
    }]
  ]
}
// Now you can use the plugin also for jest.mock calls:
jest.mock('~/myfile')

Don’t let ESLint be confused

If you use eslint-plugin-import
to validate imports it may be necessary to instruct ESLint to parse root imports. You
can use
eslint-import-resolver-babel-plugin-root-import

  "settings": {
    "import/resolver": {
      "babel-plugin-root-import": {}
    }
  }

You may also specify a prefix/suffix if it doesn’t correctly find your babel config.

  "settings": {
    "import/resolver": {
      "babel-plugin-root-import": {
        "rootPathPrefix": "~",
        "rootPathSuffix": "src"
      }
    }
  }

Don’t let Flow be confused

If you use Facebook’s Flow for type-checking it is necessary
to instruct it on how to map your chosen prefix to the root directory. Add the
following to your .flowconfig file, replacing {rootPathPrefix} with your chosen
prefix (minus a trailing slash if any) and {rootPathSuffix} with your chosen suffix.

[options]
module.name_mapper='^{rootPathPrefix}/\(.*\)$' -> '<PROJECT_ROOT>/{rootPathSuffix}/\1'

Don’t let VSCode be confused

For features like go-to-definition, VSCode needs to be able to resolve
require/import paths to files on disk. This only works with one rootPathSuffix,
but you may define multiple rootPathPrefix entries.

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "{rootPathPrefix}/*": ["src/*"]
    }
  }
}

For example, with ~/x/y.js -> ./src/x/y.js:

{
  "compilerOptions": {
    "baseUrl": ".",
    "paths": {
      "~/*": ["src/*"]
    }
  }
}

FYI

Webpack delivers a similar feature, if you just want to prevent end-less import
strings you can also define aliases in the resolve module, at the moment it
doesn’t support custom/different symbols and multiple/custom suffixes.
READ MORE

Want to revert back to relative paths?

Sometimes tooling might not be up to scratch, meaning you lose features such as
navigation in your IDE. In such cases you might want to revert back to using relative
paths again. If you have a significant amount of files, it might be worth looking into
tooling to help you with the
conversion.

Change Log

6.6.0 - 2020-10-23

support template literals in dynamic import/require

6.4.1 - 2019-07-18

fixes unicode paths on windows

6.4.0 - 2019-07-18

add support for require.resolve
add support to configure additional require-like functions

6.3.0 - 2019-07-17

Adds ‘root’ config option.

6.2.0 - 2019-05-09

Remove the 2 characters restriction

6.1.0 - 2018-06-23

Supports babel 7

5.0.0 - 2017-02-10

More consistent name: babel-plugin-root-import
#63
Renamed everything
Publish with new name on npm

4.1.5 - 2016-11-17

Compile new version and release again

4.1.4 - 2016-11-15

Improve support for relative paths (e.g. referencing parent folders via ../) (thanks
to @Hizoul)

4.1.3 - 2016-09-14

Support paths (thanks to @sivael)

4.1.0 - 2016-08-20

Use relative paths instead of absolute ones (thanks to
@nescalante)

4.0.0 - 2016-06-29

Almost everything changed, thanks to @sheepsteak,
@gingur, @olalonde

3.2.2 - 2016-02-20

Fix custom suffix in path, missing / in generated paths

3.2.0 - 2016-02-19

Support
Windows-Filesystem
Add possibility to configure a custom rootPath-Symbol (instead of ~ you can use
whatever you like)

3.1.0 - 2015-12-01

Add possibility config the custom root path

3.0.1 - 2015-11-30

Updated plugin to new babel6 API
Splitted tests and functions into two scopes with single tests
Removed the “extra-root” param for the .babelrc since this is no yet supported in
babel6

2.0.1 - 2015-11-15

Breaking Change to Babel 5

Updated to Babel 6
Added integration tests

1.0.1 - 2015-08-07

Added / updated tests
Implemented ESlint