如何调用函数,作为"新对象",并再次调用函数？

Question

作为一种学习体验,我正在尝试创建自己的面向对象的小控制台调试脚本.我希望它类似于jQuery,因为你可以将它称为函数(jQuery('div'))或对象(jQuery.ajax()).

我有下面的代码几乎正常工作.它基本上是"console.log"的别名.

我的目标是能够执行以下操作:

var log = new RadDebug;
// Create our function

log('You selected: %s', fruit_type);
// Invoke the top-level function
// Output: You selected: "Apple"

log.warn('You selected: %s', fruit_type);
// Invoke a method "warn", which displays a caution icon next to the log.
// Output: (!) You selected "Apple"

---

我正在处理的脚本:

function RadDebug() {
  var debug_enabled = (debug_mode && window.console && window.console.log instanceof Function);

  // If this object was already initialize, redirect the function call to the ".log()" as default
  if ( this.initialized ) {
    return this.log.apply( this, arguments );
  }
  this.initialized = true;

  this.log = function() {
    if ( !debug_enabled ) return;
    console.log.apply( console, arguments );
  };

  this.info = function() {
    if ( !debug_enabled ) return;
    console.info.apply( console, arguments );
  };

  // More methods below
}

---

问题:

呼叫log.warn("hello world")按预期工作.

打电话log("hello world")告诉我TypeError: Object is not a function.

问题:如何使其作为一个函数工作并具有类似对象的属性？(就像jQuery一样)

(感谢@FelixKling已经解决了这个问题.如果要查看,最终的代码可以作为Gist获得).

Answer 1

不要使用RadDebug构造函数,只需将方法附加到函数本身.

例如:

var RadDebug = (function() {
  // Some IIFE to keep debug_enabled and functions local
  var debug_enabled = (debug_mode && window.console && window.console.log instanceof Function);

  // Functions here
  function log() {
    if ( !debug_enabled ) return;
    console.log.apply( console, arguments );
  }

  function info() {
    if ( !debug_enabled ) return;
    console.info.apply( console, arguments );
  }

  // ...

  // Attach methods to "main" log function
  log.log = log;
  log.info = info;
  // ...

  // Return log function (RadDebug === log)
  return log;
}());

然后你用它作为

RadDebug('You selected: %s', fruit_type);
// same as
RadDebug.log('You selected: %s', fruit_type);

RadDebug.info('You selected: %s', fruit_type);

或RadDebug任何你想要的别名(例如log).