Pilequire

Provides an easy way to install a set of transpilers/compilers for a file extension so that modules can be compiled on-demand when they are require()'d.

Disclaimer

This module relies on the deprecated require.extensions. Even though require.extensions is likely to never be removed, don't use pilequire for modules that you want others to depend on. Instead, you should compile all source code to javascript up front before publishing.

That said, require.extensions is still widely used (e.g. by coffee-script, traceur-compiler, etc.) for these kinds of scenarios, and I have not been able to find any good replacement. If you know of a better solution, please let me know.

Use pilequire to register a set of source transforms/transpilers to run on a given extension, for example:

React JSX w/ES6 syntax => valid es6 => valid es5

var pilequire = require("pilequire");

function compileJSX2JS(filename, source) {
  // compile and return jsx
}
function compileES62ES5(filename, source) {
  // compile es6 into es5
}

// Allows you to write React JSX with ECMAScript 6 syntax
pilequire.install('.jsx', [compileJSX2JS, compileES62ES5]);

// Compiles all other `.js` files from ECMAScript 6 to ECMAScript 5
pilequire.install('.js', compileES62ES5);

The compile functions are applied in the given order, and the source parameter of each is the return value of the previous compile function

Usage

pilequire.install(extension, transform(s), [filterFn])

Where:

• extension is a string with the file extension to transform, including a leading dot, i.e. .js
• transform(s) is either a single function or an array of transform/compile functions with the signature function(filename, source) {...}
• filterFn(filename) is an optional function that is called for every require()d file and should return true or false depending on whether the file should be transformed for not. Use this to e.g. exclude files from the node_modules folder:

var EXCLUDE = /.*node_modules/;
pilequire.install('.js', compileES6, function(filename) {
  return !EXCLUDE.test(filename)
});

Full working example

// -- Compile ES6
var traceur = require("traceur");

// Make sure the traceur runtime is loaded
require(require.resolve(traceur.RUNTIME_PATH));

function compileES6(filename, contents) {

  var result = traceur.compile(contents,  { filename: filename, modules: 'inline' });

  if (result.errors.length > 0) {
    throw new Error(result.errors.join("\n"));
  }

  return result.js;
}

// -- Compile JSX
var React = require("react-tools");

// Import everything in the transformer codepath before we add the import hook
// Based on https://github.com/petehunt/node-jsx
React.transform('');

module.exports = compileJSX;

function compileJSX(filename, src) {
  try {
    return React.transform(src);
  } catch (e) {
    throw new Error('Error transforming ' + filename + ' to JSX: ' + e.toString());
  }
}

var pilequire = require('..');

var EXCLUDE = /.*node_modules/;
function filterFn(filename) {
  return !EXCLUDE.test(filename)
}
// Register compilers for .jsx and .js
pilequire.install('.jsx', [compileJSX, compileES6], filterFn);
pilequire.install('.js', compileES6, filterFn);

// Now the React component written with ES6 and JSX can be require()'d
var SomeComponent = require("./SomeComponent");

// So can regular .js-files with es6 syntax
var moduleWrittenInEs6 = require("./es6");