Editions is a backwards compatible standard for describing the ways in which your project has been produced to accelerate manual consumption, as well as automatic consumption through Ecosystem Tooling.

Why use Editions?

JavaScript production and consumption has gotten difficult over the years.

Production use to be as easy as publishing your source code, which worked across all environments, with a few minor tweaks. Consumption was as easy as including the package, and you are done.

However, these days, code may be run anywhere, in all sorts of browsers, desktop environments, and devices, of varying capabilities, not always known by the producer. JavaScript has also evolved, incorporating a lot of modern features that save developers time, but not supported across all possible environments - either requiring abstinence of time saving features, or eliminating environment support, or compilation on either the producer or consumer side - this is all complex and difficult to manage.

Editions comes in to solve this problem, elegantly, and in a standardised way, that works with current environments and development setups. Producers are able to produce their packages in their ideal configurations, then publish the package with multiple editions for the consumers to consume at their digression. Consumers are made aware of this through automated README updates, and can select the exact edition that meets their exact needs - and by default, the best edition for the environment can be automatically loaded. All the complexity of modern JavaScript publishing is solved, for the consumer and publisher.

If you wish to delve further, refer to the Alternative Approaches document for a complete understanding of the problem space and why editions is a superior solution in it.

Defining Editions

An edition is each variation of your code. Usually this comes in the form of your source edition, as well as compiled editions for each environment you wish to support.

How do I define an Edition?

Practically, editions are specified in descending order of preference in the editions field of your package.json , with each edition being composed of the following fields:

• a description field to describe the edition

• a directory field for where the edition is located

• a entry field for the default file inside the directory to be loaded

• an optional tags field for common keywords to describe the edition that tooling can utilise

You can find the full technical specification here:

Example Editions Definition

For a project that has a source edition written in ESNext using require('some-package') syntax, with a compiled edition for the default browsers, as well as a compiled edition for older node versions, then a compatible editions definition for it would look like so:

package.json
{
  "editions": [
    {
      "description": "esnext source code with require for modules",
      "directory": "source",
      "entry": "index.js",
      "tags": [
        "javascript",
        "esnext",
        "require"
      ],
      "engines": {
        "node": ">=6",
        "browsers": false
      }
    },
    {
      "description": "esnext compiled for browsers with require for modules",
      "directory": "edition-browsers",
      "entry": "index.js",
      "tags": [
        "javascript",
        "require"
      ],
      "engines": {
        "node": false,
        "browsers": "defaults"
      }
    },
    {
      "description": "esnext compiled for node.js >=0.8 with require for modules",
      "directory": "edition-node-0.8",
      "entry": "index.js",
      "tags": [
        "javascript",
        "require"
      ],
      "engines": {
        "node": ">=0.8",
        "browsers": false
      }
    }
  ]
}

Automatic Creation of Editions

Tools like Boundation can automatically create for you the editions definition as well as the editions themselves.

Consuming Editions

Editions can be consumed in multiple ways, here are the options:

A Specified Edition

For producers who only want one edition to be used by default, they can specify the default edition to be loaded via the standard main property of the package.json file:

package.json
{
  "main": "edition-node-0.8/index.js"
}

Best Edition for the Environment

For producers who want consumers to automatically load the best edition for the consumers particular environment, you can make use of the Editions Autoloader package.

1. Inside your project, install the Editions Autoloader package via npm install --save editions

2. Create a root index.js file that uses the Editions Autoloader to load the best edition from our available compatible editions.

   index.js
   'use strict'
   /** @type {typeof import("./source/index.js") } */
   module.exports = require('editions').requirePackage(__dirname, require)

3. Set the package.json property main to point to the index.js file above, instead of a specfic edition.

   package.json
   {
     "main": "index.js"
   }

Custom Entry Points

For binary executables or testing, we then we would want to specify a non-default entry to load for the editions. We can do this by passing the custom entry point as an extra argument to the requirePackage function.

To specify a bin.js custom entry, then we would perform the following.

1. Create a root bin.js file that uses the Editions Autoloader to load the best bin.js script from our available compatible editions.

   bin.js
   #!/usr/bin/env node
   'use strict'
   /** @type {typeof import("./source/bin.js") } */
   module.exports = require('editions').requirePackage(__dirname, require, 'bin.js')

2. Set the bin property in our package.json file to point to the root bin.js file we just created.

   package.json
   {
     "bin": "bin.js"
   }

To specify a test.js custom entry, then we would perform the following.

1. Create a root test.js file that uses the Editions Autoloader to load the best test.js script from our available compatible editions.

   bin.js
   'use strict'
   /** @type {typeof import("./source/test.js") } */
   module.exports = require('editions').requirePackage(__dirname, require, 'test.js')

2. Set the scripts.test property in our package.json file to point to the root test.js file we just created.

   package.json
   {
     "scripts": {
       "test": "node ./test.js"
     }
   }

Manually Require a Specific Edition

For consumers who are informed about the particular editions that an editioned package offers, they can opt into a non-standard edition by specifying it manually in their consumption.

// using require
require('a-editioned-package/a-custom-edition/')
​
// using import
import blah from 'a-editioned-package/a-custom-edition/'

Browser Edition

For our Example Editions Definition from earlier, we would define the browser field in our package.json like so:

package.json
{
  "browser": "edition-browsers/index.js"
}

This usage of the browser field tells most tools like Browserify, WebPack, and Rollup to specifically use the edition that we precompiled for the browsers we target for.

You can find more information about the browser field and its equivalents here:

You can find tooling that already has builtin support for the Editions specification here:

Documenting Editions

If producers wish to inform consumers of the editions they provide, which is not necessary for consumption, but useful to the consumer, then producers can utilise Projectz to inject the appropriate editions information into your README.md file via the HTML comment <!-- INSTALL --> .

Automatic Editions Rendering without the Editions Autoloader

If we partner our Example Editions Definition from earlier with the following package.json fields:

package.json
{
  "main": "editions-node-0.8/index.js"
}

This will have Projectz turn the <!-- INSTALL --> comment in our README.md file into the following rendered output:

​Editions​

• require('project') aliases require('project/edition-node-0.8')

• require('project/source') is ESNext source code with require for modules​

• require('project/edition-browsers') is ESNext compiled for browsers with require for modules​

• require('project/edition-node-0.8') is ESNext compiled for Node.js >=0.8 with require for modules​

Automatic Editions Documentation with the Editions Autoloader

If we partner our Example Editions Definition from earlier to make use of the Editions Autoloader, then Projectz will turn the <!-- INSTALL --> comment in our README.md file into the following rendered output:

​Editions​

• require('project') aliases require('project/index.js')which uses the Editions Autoloader to automatically select the correct edition for the consumers environment

• require('project/source') is ESNext source code with require for modules​

• require('project/edition-browsers') is ESNext compiled for browsers with require for modules​

• require('project/edition-node-0.8') is ESNext compiled for Node.js >=0.8 with require for modules​