node_modules_builder.js

/* Node modules builder for components */

var fs = require('fs')
  , _ = require('lodash')
  , mkdirp = require('mkdirp')
  , path = require('path');

var NodeModulesBuilder = function(tree, base) {
  this.traverseCache = {};
  this.buildNodeModules(tree);
};

_.extend(NodeModulesBuilder.prototype, {
  buildNodeModules: function(node) {
    var self = this, deps;

    // Short circuite if the dependency has already been modulized
    if (this.traverseCache[node.name]) {
      return;
    } else {
      this.traverseCache[node.name] = true;
    }

    // Make sure the component has an index.js/jsx
    // to be compatible with default node lookup
    if (node.type == 'dependency' && !this.hasEntryPoint(node)) {
      this.createDependencyEntryPoint(node);
    }

    // Create a node_modules folder if none exists
    this.createNodeModulesFolder(node);

    deps = _.union(_.values(node.locals), _.values(node.dependencies));
    _.each(deps, function(dep) {
      self.buildNodeModules(dep);
      self.linkDepLocally(node, dep);
    });
  },

  linkDepLocally: function(source, target) {
    var sourceNodeModules = path.join(source.path, 'node_modules')
      , pathSegments = target.node.name.split(path.sep)
      , symlinkTarget, symlinkTargetHead, symlinkTargetTail;

    if (pathSegments.length > 1 ) {
      // We need to make some nesting dirs first
      symlinkTargetHead = pathSegments.pop()
      symlinkTargetTail = path.join(
        sourceNodeModules,
        pathSegments.join(path.sep)
      );

      mkdirp.sync(symlinkTargetTail);
      symlinkTarget = path.join(symlinkTargetTail, symlinkTargetHead);
    } else {
      symlinkTarget = path.join(sourceNodeModules, target.node.name);
    }

    if (fs.existsSync(symlinkTarget)) {
      if (fs.readlinkSync(symlinkTarget) !== target.path) {
        fs.unlinkSync(symlinkTarget);
        fs.symlinkSync(target.path, symlinkTarget);
      }
    } else {
      fs.symlinkSync(target.path, symlinkTarget);
    }
  },

  createNodeModulesFolder: function(node) {
    var nodeModulesPath = path.join(node.path, 'node_modules');
    if (!fs.existsSync(nodeModulesPath)) {
      fs.mkdirSync(nodeModulesPath);
    }
  },

  hasEntryPoint: function(node) {
    var jsEntryPoint = path.join(node.path, 'index.js')
      , jsxEntryPoint = path.join(node.path, 'index.jsx');
    return fs.existsSync(jsEntryPoint) ||
           fs.existsSync(jsxEntryPoint);
  },

  createDependencyEntryPoint: function(node) {
    var entryPoint = path.join(node.path, node.node.main)
      , canonicalEntryPoint = path.join(
        node.path,
        node.node.main.match(/jsx$/) !== null ? 'index.jsx' : 'index.js'
      );

    fs.symlinkSync(entryPoint, canonicalEntryPoint);
  },
});

module.exports = function(tree, base, cb) {
  var builder = new NodeModulesBuilder(tree, base);
  return cb();
};