Question

我最近使用Dojo toolkit构建了一个项目，并且非常喜欢如何将一段代码标记为仅包含在基于任意conditional check的编译版本中。我用它来导出私有变量进行单元测试或抛出错误而不是记录它们。这是Dojo格式的一个例子，我很想知道Google Closure Compiler是否有这样的特殊指令。

window.module = (function(){

  //private variable
  var bar = {hidden:"secret"};

  //>>excludeStart("DEBUG", true);
    //export internal variables for unit testing 
    window.bar = bar;
  //>>excludeEnd("DEBUG");

  //return privileged methods
  return {
    foo: function(val){
      bar.hidden = val;
    }
  };
})();

修改

关闭权威指南提到您可以扩展CommandLineRunner以添加您自己的检查和优化，这可能是一种方法。 Plover看起来很有前途，因为它支持custom-passes。

Answer 1

这个简单的测试案例奏效了。使用--define DEBUG=false

进行编译

/**
 * @define {boolean} DEBUG is provided as a convenience so that debugging code
 * that should not be included in a production js_binary can be easily stripped
 * by specifying --define DEBUG=false to the JSCompiler. For example, most
 * toString() methods should be declared inside an "if (DEBUG)" conditional
 * because they are generally used for debugging purposes and it is difficult
 * for the JSCompiler to statically determine whether they are used.
 */
var DEBUG = true;

window['module'] = (function(){

  //private variable
  var bar = {hidden:"secret"};

  if (DEBUG) {
    //export internal variables for unit testing 
    window['bar'] = bar;
  }

  //return privileged methods
  return {
      foo: function(val){
        bar.hidden = val;
      }
  };
})();

console.log(window['bar']);
module.foo("update");
console.log(window['bar']);

Answer 2

Closure Compiler支持“定义”，如下所示：

/** @define {boolean} */
var CHANGABLE_ON_THE_COMMAND_LINE = false;

使用Google Closure Compiler可以从编译版本中排除一部分源代码吗？

2 个答案: