import-js

3.1.0 • Public • Published

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ImportJS is a tool to automatically import dependencies in your JavaScript project. Use it along with one of our editor integrations for Atom, Emacs, Sublime, Vim, or VS Code.

Demo of ImportJS in action

Editor support

There are ImportJS plugins for the following editors:

Detailed instructions on how to install ImportJS can be found in the editor links above.

Want to add another editor to the list? See how to contribute.

Importing: Example

Let's say that you have a JavaScript project with the following structure:

.
|-- index.html
|-- components
|     |-- button.js
|     |-- icon.js
|-- vendor
|     |--
|-- pages
|     |-- index.js

Now, imagine that you're editing pages/index.js which contains:

document.createElement(new Button({ text: 'Save' }).toDOMElement());

At this point, Button is undefined, so we need to import it. If you are used to doing this manually, this involves figuring out the path to the JavaScript module that defines Button. With ImportJS you instead place your cursor on the word "Button", then hit <leader>j (Vim), (M-x) import-js-import (Emacs), or choose "ImportJS: import word under cursor" (Sublime). The file buffer will now change to the following:

import Button from '../components/button';
 
document.createElement(new Button({ text: 'Save' }).toDOMElement());

That's basically it. ImportJS will help you find modules and automatically add import statements. But, keep reading for more neat features.

Fix imports

ImportJS can be used to automatically fix all imports in the current file. By hitting <leader>i (Vim), (M-x) import-js-fix (Emacs), or choose ImportJS: fix all imports (Sublime), all your undefined variables will be resolved, and all your unused imports will be removed.

If you're using JSX, ImportJS will automatically import React for you.

Go to module

Since ImportJS is pretty good at finding JS modules, it makes sense that there's an option to open/go to a file rather than import it. This is similar to Vim's built in "Open file under cursor". Use it by placing the cursor on a variable and hit <leader>g (Vim), (M-x) import-js-goto (Emacs), or choose "ImportJS: goto module" (Sublime).

Things to note

  • Only files ending in .js\* and .ts* are considered when importing
  • As part of resolving imports, all imports will be sorted and placed into groups. Grouping and sorting can be disabled, see the groupImports and sortImports configuration options. Comments and whitespace will be preserved if these are both disabled.
  • You can speed up ImportJS by installing Watchman. See Speeding it up! for more information.

Configuration

ImportJS is configured through a JavaScript file (.importjs.js).

The file needs to export a single object containing you configuration settings, like the example below.

module.exports = {
    excludes: [
        './react-components/**/test/**'
    ]
    // continue with the rest of your settings...
}

Save this file in the root folder of your project (e.g. where the package.json file is found). You can also save it to the user home directory if you want to share a global config between different projects.

The following configuration options are supported.

excludes

Define a list of glob patterns that match files and directories that you don't want to include for importing.

excludes: [
  './react-components/**/test/**',
]

aliases

Some variable names might not easily map to a file in the filesystem. For those, you can add them to the aliases configuration.

aliases: {
  $: 'third-party-libs/jquery',
  _: 'third-party-libs/underscore',
}

Aliases can be made dynamic by using the {filename} string. This part of the alias will be replaced by the name of the file you are currently editing.

e.g.

aliases: {
  styles: './{filename}.scss',
}

will for a file foo/bar.js result in

import styles from './bar.scss';

environments

This list of environments controls what core modules are available when importing, and what variables are considered global by default. The supported values right now are

environments: ['meteor', 'node']

namedExports

*Note: Since 2.1.0 ImportJS finds your named exports automatically. Most likely you don't need this option. If you end up having to use this configuration anyway, there might be a bug in the exports-finding parts of ImportJS. File an issue and tell us about it!

If you have an ES6/ES2015 module that exports multiple things (named exports), or a CommonJS module that exports an object with properties on it that you want to destructure when importing, you can add those to a namedExports configuration option.

namedExports: {
  underscore: [
    'omit',
    'debounce',
    'memoize'
  ],
  'lib/utils': [
    'escape',
    'hasKey',
  ],
}

Imports that use the import declaration keyword then use named imports syntax. e.g.

import { memoize } from 'underscore';
 
memoize(() => { foo() });

and imports that use const or var use [ES2015 Destructuring Assigment][destructing assignment], e.g.

const { memoize } = require('underscore');
 
memoize(() => { foo() });

The key used to describe the named exports should be a valid import path. This can be e.g. the name of a package found under node_modules, a path to a module you created yourself, or a relative import path.

declarationKeyword

The default value for this property is import, making your import statements use the ES2015 modules syntax:

import Foo from 'foo';

If you aren't ready for ES2015 yet, you have the option to use var or const instead.

declarationKeyword: 'const'

In such case, your import statements will look something like this:

var Foo = require('foo'); // "declarationKeyword": "var"
const Foo = require('foo'); // "declarationKeyword": "const"

globals

Provide a list of global identifiers used in the code. ImportJS will ignore these when trying to import all undefined variables.

Note: If you use the environments configuration option correctly, you might not need to specify globals.

groupImports

By default, ImportJS will put imports into groups:

  1. Core modules
  2. Package dependencies
  3. One or more groups with internal imports

You can turn off this behavior by setting groupImports to false. When disabled, imports are listed alphabetically in one list.

groupImports: false

sortImports

By default, ImportJS will sort imports by the name or path of the imported module.

You can turn off this behavior by setting sortImports to false. When disabled, existing imports are not rearranged, and new imports are always added above existing imports.

sortImports: false

emptyLineBetweenGroups

By default, ImportJS will insert empty line between import groups.

You can turn off this behavior by setting emptyLineBetweenGroups to false.

emptyLineBetweenGroups: false

importDevDependencies

ImportJS will look for package dependencies listed in package.json when importing. By default, only modules listed under dependencies and peerDependencies will be used. By setting importDevDependencies to true, devDependencies will also be taken into account.

importDevDependencies: true

danglingCommas

By default, ImportJS will add trailing commas when constructing import statements with multiple named imports.

You can turn off this behavior by setting danglingCommas to false.

danglingCommas: false

importFunction

Note: this only applies if you are using var or const as declarationKeyword.

The default value for this configuration option is "require", which is the standard CommonJS function name used for importing.

importFunction: 'myCustomRequireFunction'

stripFileExtensions

An array that controls what file extensions are stripped out from the resulting import statement. The default configuration strips out [".js", ".jsx", ".ts", ".tsx"]. Set to an empty array [] to avoid stripping out extensions.

stripFileExtensions: ['.web.js', '.js']

useRelativePaths

This option is enabled by default. When enabled, imports will be resolved relative to the current file being edited.

import Foo from './foo';
import Bar from '../baz/bar';

You can disable this by setting it to false:

useRelativePaths: false

Package dependencies (located in node_modules) will not be imported relatively.

ignorePackagePrefixes

If you have package dependencies specified in package.json that are prefixed with e.g. an organization name but want to be able to import these without the package prefix, you can set the ignorePackagePrefixes configuration option.

ignorePackagePrefixes: ['my-company-']

When package dependencies are matched, these prefixes will be ignored. As an example, a variable named validator would match a package named my-company-validator.

minimumVersion

Setting minimumVersion will warn people who are running a version of ImportJS that is older than what your .importjs.js configuration file requires. If your plugin version is older than this value, you will be shown a warning that encourages you to upgrade your plugin.

minimumVersion: '1.0.0'

maxLineLength

Defaults to 80. This setting controls when import statements are broken into multiple lines.

maxLineLength: 70

moduleNameFormatter

Use a function here to control how the resulting module name string will look like. It's useful if you for instance want to add a custom prefix to certain imports. Apart from the standard pathToCurrentFile and pathToImportedModule values passed in to all configuration functions, this method is also passed a moduleName value, which in general is what you want to manipulate.

moduleNameFormatter({ moduleName, pathToCurrentFile }) {
 if (/-test/.test(pathToCurrentFile)) {
   // Import a mocked version in test files
   return `mocks/${moduleName}`;
 }
 
 if (moduleName.startsWith('foo')) {
   // Add a leading slash to foo imports
   return `/${moduleName}`;
 }
 
 // Fall back to the original specifier. It's important that this function
 // always returns a string.
 return moduleName;
},

importStatementFormatter

Use a function here to control how the resulting import statement will look like. This is useful if you for instance want to strip out trailing semicolons (that ImportJS adds by default).

Note: this method should only be used in rare cases. There's a chance that ImportJS won't be able to recognize the resulting import statement next time it is about to import something.

importStatementFormatter({ importStatement }) {
  return importStatement.replace(/;$/, '');
},

tab

Defaults to two spaces (" "). This setting controls how indentation is constructed when import statements are broken into multiple lines.

tab: '\t'

logLevel

One of ["debug", "info", "warn", "error"]. This controls what ends up in the logfile. The default is info.

logLevel: 'debug'

The logfile is written to "importjs.log" in your operating system's default directory for temporary files. You can get the path to the log file by running importjsd logpath.

mergableOptions

A dictionary of Options that be merged with defaults and values provided by an environment. This can be used to overwrite options provided by environments. Defaults to:

mergableOptions: {
  aliases: true,
  coreModules: true,
  namedExports: true,
  globals: true,
}

Note: the mergableOptions option will always be merged and will be ignored if included in a user config.

To disable merging a particular option or set of options, set the key to false:

mergableOptions: {
  globals: false
}

For example, if you are using the meteor environment but want to explicitly import modules which are provided as globals, you can use this setting to overwrite the environment globals.

const globals = require('globals');
module.exports = {
  environments: ['meteor', 'node'],
  mergableOptions: {
    globals: false // Overwrite globals
  },
  globals: [
    // Add the globals you want back in
    ...Object.keys(globals.builtin), // include javascript builtins
    ...Object.keys(globals.node), // include node globals
    'Package', 'Npm' // Include meteor globals for `package.js` files
  ]
}

Dynamic configuration

Different sections of your application may have special importing needs. For instance, your tests might need the 'const' declaration keyword, but the rest of your application can use 'import'. To be able to target these special cases, you can turn your configuration option into a function. When ImportJS resolves a configuration option, it will check to see if a function is used. In such case, the function is invoked with the following arguments:

  • pathToCurrentFile: (always available) A path to the file you are editing.
  • pathToImportedModule (not available for some options) A path to the file/module you are importing.

Here's an example of how to dynamically control the declarationKeyword configuration option based on the file you are importing:

// .importjs.js
function isTestFile(path) {
  return path.endsWith('-test.js');
}
 
module.exports {
  declarationKeyword({ pathToImportedModule }) {
    if (isTestFile(pathToImportedModule)) {
      return 'const';
    }
    return 'import';
  },
}

Here's a more elaborate example taking both pathToImportedModule and pathToCurrentFile into account:

module.exports {
  useRelativePaths({ pathToImportedModule, pathToCurrentFile }) {
    if (pathToCurrentFile.endsWith('-mock.js')) {
      return false;
    }
    if (pathToImportedModule.endsWith('-test.js')) {
      return false;
    }
    return true;
  },
}

In order to use functions, you need to use the JavaScript configuration file (.importjs.js).

Command-line tool

ImportJS comes with a handy command-line tool that can help you perform importing outside of an editor. Under the hood, this is what most of the editor integrations use.

⨠ importjs --help
 
  Usage: importjs [options] [command]
 
 
  Commands:
 
    word [options] <word> <pathToFile>
    search [options] <word> <pathToFile>
    fix [options] <pathToFile>
    rewrite [options] <pathToFile>
    add [options] <imports> <pathToFile>
    goto <word> <pathToFile>
    start [options]                       start a daemon
    cachepath                             show path to cache file
    logpath                               show path to log file
 
  Options:
 
    -h, --help     output usage information
    -V, --version  output the version number
 
  Examples:
 
    $ importjs word someModule path/to/file.js
    $ importjs search someModule* path/to/file.js
    $ importjs fix path/to/file.js
    $ importjs rewrite --overwrite path/to/file.js
    $ importjs add '{ "foo": "path/to/foo", "bar": "path/to/bar" }' path/to/file.js
    $ importjs goto someModule path/to/file.js
    $ importjs cachepath
    $ importjs logpath
    $ importjs start --parent-pid=12345

Batch-rewriting

If you want to change how imports are constructed in an existing project, you can use the command-line tool in combination with find to batch-update a set of files. E.g.

find ./app -name "**.js*" -exec importjs rewrite --overwrite {} \;

Since the --overwrite flag makes ImportJS destructive (files are overwritten), it's a good thing to double-check that the find command returns the right files before adding the -exec part.

Running as a daemon

Note: This section is intended mostly for developers of editor plugins. If you are using one of the standard editor plugins, you are most likely using the daemon under the hood already.

You can run ImportJS in a background process and communicate with it using stdin and stdout. This will make importing faster because we're not spinning up a node environment on every invocation.

The daemon is started by running running importjsd. It accepts commands sent via stdin. Each command is a (oneline) JSON string ending with a newline. The command structure is basically the same as for the command-line tool, but wrapped in JSON instead of expressed on the command line. Here are a few examples:

Run fix imports:

{
  "command": "fix",
  "fileContent": "const foo = bar();\n",
  "pathToFile": "foo.js",
}

Import a single word:

{
  "command": "word",
  "commandArg": "bar",
  "fileContent": "const foo = bar();\n",
  "pathToFile": "foo.js",
}

Goto:

{
  "command": "goto",
  "commandArg": "bar",
  "fileContent": "const foo = bar();\n",
  "pathToFile": "foo.js",
}

Results are printed to stdout in JSON format. The response will look the same as what the command-line tool produces. If an error occurs, it will also end up in stdout as JSON (an object with an error key).

On startup, the daemon will print a path to a logfile. If you want to find out what's going on behind the scenes, you can inspect this file. If you don't have access to the console log of the daemon, you'll find the logfile in os.tmpdir() + '/importjs.log (which will resolve to something like var/folders/1l/_t6tm7195nd53936tsvh2pcr0000gn/T/importjs.log on a Mac).

Speeding it up!

If you have a large application, traversing the file system to find modules can be slow. That's why ImportJS has built-in integration with Watchman, a fast and robust file watching service developed by Facebook. All you have to do to get a performance boost is to install watchman locally, and make sure to use an up-to-date editor plugin (Watchman is only used when ImportJS is run as a daemon).

Contributing

See the CONTRIBUTING.md document for tips on how to run, test and develop ImportJS locally.

Thank you:

  • @janpaul123 for writing the Sublime plugin.
  • @kevinkehl for getting the parentheses right for the Emacs plugin
  • @rhettlivingston for making import-js work for Meteor, and for driving the development forward by bringing in lots of experience and great ideas.
  • @dabbott for writing the VS Code plugin.

Happy hacking!

install

npm i import-js

Downloadsweekly downloads

20,953

version

3.1.0

license

MIT

homepage

github.com

repository

Gitgithub

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