barrelsby

Automatically create TypeScript barrels for your entire code base.

About Barrels

Barrels are files that rollup exports from several modules into a single convenient module typically named index.ts. They tend to help simplify large blocks of import statements at the top of files and help to group up related functionality.

A barrel file looks like this:

export * from "./DropDown";
export * from "./TextBox";
export * from "./CheckBox";
export * from "./DateTimePicker";
export * from "./Slider";

It can help you go from messy imports like this:

import {DropDown} from "./src/controls/DropDown";
import {TextBox} from "./src/controls/TextBox";
import {CheckBox} from "./src/controls/CheckBox";
import {DateTimePicker} from "./src/controls/DateTimePicker";
import {Slider} from "./src/controls/Slider";

...to something tidier like this:

import {DropDown, TextBox, CheckBox, DateTimePicker, Slider} from "./src/controls";

...or even this:

import * as Controls from "./src/controls/index";

More Reading

• TattooCoder Blog

Barrelsby Articles

• Rupesh Tiwari Blog
• Medium Article

Alternatives

• Barrelbot
• creeate-index

Usage

To install Barrelsby:

npm install --save-dev barrelsby

To run barrelsby first add a script to the package.json file:

{
  "scripts": {
    "generate-barrels": "barrelsby --delete"
  }
}

You can now generate barrels:

npm run generate-barrels

Configuration Options

Barrelsby accepts a number of options to help refine how your barrels are created. These options can be configured from the command line or using a configuration file.

-c [path] or --config [path]

Specifies the location of the barrelsby configuration file. This file must be a .json file. You can include any of the configuration options using their long name.

-d [path...] or --directory [path...]

Specifies a list of root directories where barrels will be created from. Uses the current directory by default.

Note: This is backwards compatible with previous versions. Existing configuration files will be parsed correctly. The following two json files will behave identically.

{
  "directory": "./src"
}

{
  "directory": ["./src"]
}

-D or --delete

Deletes any existing barrels encountered by barrelsby. Disabled by default.

-e [regex...] or --exclude [regex...]

Excludes any files whose paths match any of the specified regular expressions.

-E or --exportDefault

Also export the default export of the file. Currently works only with the flat mode.

export * from "./barrel";
export { default as barrel } from "./barrel";

-F or --fullPathname

exportDefault with full pathname to create distinct name. Currently works only with the flat mode and exportDefault flag.

export * from "./example/of/the/path";
export { default as exampleOfThePath } from "./example/of/the/path";

-h or --help

Displays help information on the command line arguments that barrelsby accepts.

-i [regex...] or --include [regex...]

Only include files whose paths match any of the specified regular expressions.

-l [mode] or --location [mode]

The mode that barrelsby should use to determine where which directories to create barrels in. Defaulted to top.

• top only creates a barrel in the target directory.
• below creates a barrel in every directory just below the target directory.
• all creates a barrel in every directory below (and including) the target directory.
• replace only creates barrels in directories where one already existed.
• branch creates a barrel in every directory that contains other directories.

-L or --local

Enable this to prevent barrels including modules that exist in the same directory, rather than recursively searching child directories.

-n [name] or --name [name]

Specifies the name to use for creating new barrels (and identifying old ones). .ts wil be appended if not included in the name. Barrels names will be defaulted to index.ts.

-s [mode] or --structure [mode]

The structure that barrelsby should create inside the barrels. Defaulted to flat.

flat

Exports modules without any nesting.

export * from "./barrel";
export * from "./index";
export * from "./directory2/script";
export * from "./directory2/directory4/deeplyNested";
export * from "./directory3/program";

filesystem

Exports modules as a nested structure that matches the file system directories.

import * as barrelts from "./barrel";
import * as directory2directory4deeplyNestedts from "./directory2/directory4/deeplyNested";
import * as directory2scriptts from "./directory2/script";
import * as directory3programts from "./directory3/program";
import * as indexts from "./index";
export {barrelts as barrel};
export const directory2 = {
  directory4: {
    deeplyNested: directory2directory4deeplyNestedts,
  },
  script: directory2scriptts,
};
export const directory3 = {
  program: directory3programts,
};
export {indexts as index};

-q or --singleQuotes

Use 'single quotes' in the generated barrel files instead of the default "double quotes".

-S or --noSemicolon

Omit semicolons from the end of lines in the generated barrel files.

-H or --noHeader

Omit adding a header comment to the top of the barrel file.

-v or --version

Display the barrelsby version number.

-V or --verbose

Display additional debug information.

Requirements

Requires node v6.0.0 or greater for ES6 syntax.

Contributing

See CONTRIBUTING.md