的javascript：通过局部变量的匿名函数

Question

问题：如何访问shortcut或action或其他局部变量

相关：类似的问题，但没有成功：

• Passing local variable to loader anonymous handler function
• how to pass local variables when assigning mouseover via anonymous function?
• javascript anonymous function parameter passing
• How to pass variable to anonymous function

Java解决方案： 设置final改性剂，在匿名函数需要

目标源代码变量：

//plugin.buttons is collection of button objects 
for (var i in plugin.buttons) { 
    var button = plugin.buttons[i]; 
    var icon = button.icon; 
    var text = button.text; 
    var shortcut = button.shortcut; 
    var action = button.action; //action is a function (or method) 

    if (shortcut != null && shortcut.length > 0) { 
     if ($.isFunction(action)) { 
      console.log(shortcut); //it's valid shortcut 
      //using jQuery hotkey plugin 
      $('div[contenteditable]').bind('keydown', shortcut, function() { 
       console.log(shortcut); //it's undefined 
       action.call(); //it's undefined also 
       return false; 
      }); 
     } 
    } 
} 

Answer 1

你可以把它作为event data

for (var i in plugin.buttons) { 
    var button = plugin.buttons[i]; 
    var icon = button.icon; 
    var text = button.text; 
    var shortcut = button.shortcut; 
    var action = button.action; //action is a function (or method) 

    if (shortcut != null && shortcut.length > 0) { 
     if ($.isFunction(action)) { 

      $('div[contenteditable]').on('keydown', {shortcut : shortcut}, function (e) { 

       console.log(e.data.shortcut); 

      }); 
     } 
    } 
} 

但是在这种情况下，真正的问题是在for循环中没有特殊的作用域，因此在for循环中定义变量只是在每次迭代时覆盖相同的变量，这就是为什么当事件处理程序将在稍后调用。

你必须在变量锁定在一个新的范围

for (var key in plugin.buttons) { 
    (function(i) { 
     var button = plugin.buttons[i]; 
     var icon = button.icon; 
     var text = button.text; 
     var shortcut = button.shortcut; 
     var action = button.action; //action is a function (or method) 

     if (shortcut != null && shortcut.length > 0) { 
      if ($.isFunction(action)) { 
       console.log(shortcut); //it's valid shortcut 
       //using jQuery hotkey plugin 
       $('div[contenteditable]').bind('keydown', shortcut, function() { 
        console.log(shortcut); //it's undefined 
        action.call(); //it's undefined also 
        return false; 
       }); 
      } 
     } 
    })(key); 
}