gendex

gendex is a cli tool that allows developers to organise exports from several JavaScript files in a given directory, into one 'master' index.js file.

gendex works with jsx files as well and by default uses ES6 when generating the index.js file. But can be configured to use ES5 (Explained in Usage section).

gendex can be used in nested directories and will recursively build an index.js file at each level.

Installation

1. Either installing gendex globally using npm or yarn:

   npm install -g gendex

   This will install gendex globally to your system path.

2. Installing gendex as dev dependency:

   npm install --save-dev gendex

   With a local installation, gendex will not be available in your system path. Instead, the local installation of gendex can be run by calling it from within an npm script.

   For example:

   In your package.json you could add the following script command:

   {
       "main": "index.js",
       "license": "MIT",
       "scripts": {
           "gendex": "gendex -d <directory>",
           "test": "echo \"Error: no test specified\" && exit 1"
       }
   }
   

   Then simply run:

   npm run gendex

Options

gendex has the following options:

Usage: gendex [options]

Options:
  -v, --version                   output the version number
  -d, --directory <directory>     choose directory
  -e, --ecma-script [js-version]  choose ECMAScript version (default: "es6")
  -h, --help                      output usage information

NOTE: -d, --directory option is required.

Usage

In the examples directory we have two nested directories es5 and es6. If you look through the JavaScript files you can see they export variables, functions, classes etc.

I will provide two examples, one will use ES5 and the other will use ES6.

Please note, gendex will generate an ES6 index.js from ES6 and ES5 JS files. But, cannot generate an ES5 index.js from ES6 JS files. The diagram below explains this further.

(EcmaScript -v)   
JS-file                     index.js
ES6         ---------->     ES6
ES5         ---------->     ES6
ES5         ---------->     ES5

ES6         --xxxxxxx->     ES5

ES5 example

We have the following tree structure.

.
+-- examples
|   +--es5
|   |   +--file-1.js // named exports {a, b}
|   |   +--file-2.js // named exports {a, b, c}
|   |   +--file-3.js // default export

By running the following command (using CLI or npm run script):

gendex -d ./examples/es5 -e es5

The following ES5 index.js file will be generated in the given directory:

// ES5

const { a, b} = require("./file-1.js");
const { a: a_1, b: b_1, c} = require("./file-2.js"); // duplicate exports changed
const file3 = require("./file-3.js"); // default export uses fileName.


module.exports = {
	a,
	a_1,
	b,
	b_1,
	c,
	file3,
}

NOTE: we could also generate an ES6 index.js, by removing the -e option from the previous command.

// ES6

import { a , b } from "./file-1.js";
import { a as a_1, b as b_1, c } from "./file-2.js";
import file3  from "./file-3.js";


export {
	a,
	a_1,
	b,
	b_1,
	c,
	file3,
}

The index.js file will take into account any duplicate exports and generate an alias. Additionally, any default exports are given the name of the file.

ES6 example

Inside the examples/es6 directory, I have a JSX and a combination of ES5 and ES6 files.

We have the following tree structure.

.
+-- examples
|   +--es6
|   |   +--file-1-es6.js // named exports {a, b}
|   |   +--file-2-es5.js // named exports {a, b, c}
|   |   +--file-3-es6.jsx // default export, named export App (component)

By running the following command (using CLI or npm run script):

NOTE: we can only generate ES6 index.js in this directory (as mentioned previously).

gendex -d ./examples/es6

The following ES6 index.js file will be generated in the given directory:

// ES6

import file1Es6 , { a } from "./file-1-es6.js";
import { a as a_1, b , c } from "./file-2-es5.js";
import file3Es6 , { App } from "./file-3-es6.jsx";


export {
	a,
	a_1,
	b,
	c,
	file1Es6,
	file3Es6,
	App,
}

Please note: Attempting to generate an ES5 index.js from ES6 JS files will result in an error.