grunt-commonizor/tasks/commonizor.js

plugin for building js file to support commonjs

/*
 * grunt-commonizor
 * wrap jsfiles to support commonjs.
 * 
 * Copyright (c) 2015 大法
 * Licensed under the MIT license.
 */

/**
 * 输出文件名：
 *   按src文件名xxx.js转为对应的xxx.js
 *
 * 模块输出（module.exports）:
 *   只有pkg名字和文件名一致的文件才会将模块用module.exports输出
 *   其他可以自行通过挂载到windows上的变量存取
 */

'use strict';

var path = require('path'),

  grunt,
  pkg,        // package

  modPkgFile = function(files, pkg, options) {

    var src = files[0].src[0],
      ext = 'common.js',
      dependencies = pkg.dependencies,
      name = pkg.name;

    grunt.log.debug('commonizor: add commonjs support for ' + name);

    if (name !== 'grunt-commonizor') {
      if (!pkg.main) {
        pkg.main = 'build/' + name + '.' + ext;
      }

      //////// 更新package.json文件
      grunt.file.write('package.json', JSON.stringify(pkg, null, 2));
      grunt.log.writeln('finished writing to package.json.');
    }

  },

  getJsRequiresFromDeps = function(deps) {
    //////// 添加deps里的依赖组件到requires里
    var requires;
    if (deps) {
      requires = Object.keys(deps).map(function(key) {
        return "'" + key + "'";
      });
    } else {
      requires = [];
    }
    return requires;
  },

  wrapWithCommonJs = function(requires, options, file) {
    //////// 合并多个源文件并打包输出commonjs文件
    var dest = file.dest,
      style = file.dest,
      name = pkg.name;

    if (file.src && file.src.length > 0) {

      grunt.log.debug('commonizor: src - ' + file.src);
      var jsFile = '';

      //////// 拼接require依赖声明
      jsFile += '(typeof window === \'undefined\') && (window = {ctrl: {}, lib: {}});!window.ctrl && (window.ctrl = {});!window.lib && (window.lib = {});';
      for (var i = 0, l = requires.length; i < l; i++) {
        jsFile += 'require(' + requires[i] + ');';
      }

      //////// 拼接多个源文件
      file.src.forEach(function(f, idx) {
        var src = f;
        grunt.log.debug('commonizor: handleing with file \'' + src + '\'');
        if (!src.match(/\.js$/)) {
          grunt.fail.fatal('Source file must be a js file.');
        }
        jsFile += grunt.file.read(src);
      });

      file.src.forEach(function(f, idx) {
        if (name === path.basename(f, '.js')) {
          // 如果是组件的主文件则通过module.exports输出
          // 如果有type则输出的是window[type][name]，如果没有则输出的是window[name]
          jsFile += ';module.exports = window.lib' + '[\'' + name + '\'];';
        }
      });

      grunt.log.debug('commonizor: saving file - ' + dest);
      grunt.file.write(dest, jsFile);
      grunt.log.writeln('File "' + dest + '" created.');
    } else {
      grunt.fail.fatal('Source file "' + file.orig.src + '" not found.');
    }

  };

module.exports = function(gt) {

  grunt = gt;
  
  grunt.registerMultiTask('commonizor', 'Wrap File for CommonJS', function() {
    
    var options = this.options({}),
      packageFile = options.pkg || grunt.file.readJSON('package.json'),
      dependencies = packageFile.dependencies,
      requires;  // 依赖到的文件相对路径的缓存

    pkg = packageFile;
    if (!pkg) {
      return grunt.log.error('specific "pkg" field in options');
    }
    requires = getJsRequiresFromDeps(dependencies);
    // Iterate over all specified file groups.
    this.files.forEach(wrapWithCommonJs.bind({}, requires, options));
    ///////// 将部分信息写入package.json中
    modPkgFile(this.files, pkg, options);

  });

};