jsx

#!/usr/bin/env node
"use strict";

var visitors = require('../vendor/fbtransform/visitors').transformVisitors;
var transform = require('../vendor/fbtransform/lib/transform').transform;
var propagate = require("../vendor/constants").propagate;

require("commoner").resolve(function(id) {
  var context = this;

  // Note that the result of context.getProvidedP() is cached for the
  // duration of the build, so it is both consistent and cheap to
  // evaluate multiple times.
  return context.getProvidedP().then(function(idToPath) {
    // If a module declares its own identifier using @providesModule
    // then that identifier will be a key in the idToPath object.
    if (idToPath.hasOwnProperty(id)) {
      return context.readFileP(idToPath[id]);
    }

    // Otherwise assume the identifier maps directly to a path in the
    // filesystem.
    return context.readModuleP(id);
  });

}).process(function(id, source) {
  var context = this;

  // This is where JSX, ES6, etc. desugaring happens.
  source = transform(visitors.react, source).code;

  return context.makePromise(function(callback) {
    var constants = context.config.constants || {};

    // Constant propagation means removing dead code after replacing
    // constant conditional expressions with literal (boolean) values.
    propagate(constants, source, function(source) {
      callback(null, source);
    });
  });
});