Function.prototype什么意思，Function指的是什么，不是很清楚
JScript code
/**
* @class Function
* These functions are available on every Function object (any JavaScript function).
*/
Ext.apply(Function.prototype, {
/**
* Creates an interceptor function. The passed fcn is called before the original one. If it returns false,
* the original one is not called. The resulting function returns the results of the original function.
* The passed fcn is called with the parameters of the original function. Example usage:
* <pre><code>
var sayHi = function(name){
alert('Hi, ' + name);
}
sayHi('Fred'); // alerts "Hi, Fred"
// create a new function that validates input without
// directly modifying the original function:
var sayHiToFriend = sayHi.createInterceptor(function(name){
return name == 'Brian';
});
sayHiToFriend('Fred'); // no alert
sayHiToFriend('Brian'); // alerts "Hi, Brian"
</code></pre>
* @param {Function} fcn The function to call before the original
* @param {Object} scope (optional) The scope of the passed fcn (Defaults to scope of original function or window)
* @return {Function} The new function
*/
createInterceptor : function(fcn, scope){
var method = this;
return !Ext.isFunction(fcn) ?
this :
function() {
var me = this,
args = arguments;
fcn.target = me;
fcn.method = method;
return (fcn.apply(scope || me || window, args) !== false) ?
method.apply(me || window, args) :
null;
};
},
/**
* Creates a callback that passes arguments[0], arguments[1], arguments[2], ...
* Call directly on any function. Example: <code>myFunction.createCallback(arg1, arg2)</code>
* Will create a function that is bound to those 2 args. <b>If a specific scope is required in the
* callback, use {@link #createDelegate} instead.</b> The function returned by createCallback always
* executes in the window scope.
* <p>This method is required when you want to pass arguments to a callback function. If no arguments
* are needed, you can simply pass a reference to the function as a callback (e.g., callback: myFn).
* However, if you tried to pass a function with arguments (e.g., callback: myFn(arg1, arg2)) the function
* would simply execute immediately when the code is parsed. Example usage:
* <pre><code>
var sayHi = function(name){
alert('Hi, ' + name);
}
// clicking the button alerts "Hi, Fred"
new Ext.Button({
text: 'Say Hi',
renderTo: Ext.getBody(),
handler: sayHi.createCallback('Fred')
});
</code></pre>
* @return {Function} The new function
*/
createCallback : function(/*args...*/){
// make args available, in function below
var args = arguments,
method = this;
return function() {
return method.apply(window, args);
};
},
/**
* Creates a delegate (callback) that sets the scope to obj.
* Call directly on any function. Example: <code>this.myFunction.createDelegate(this, [arg1, arg2])</code>
* Will create a function that is automatically scoped to obj so that the <tt>this</tt> variable inside the
* callback points to obj. Example usage:
* <pre><code>
var sayHi = function(name){
// Note this use of "this.text" here. This function expects to
// execute within a scope that contains a text property. In this
// example, the "this" variable is pointing to the btn object that
// was passed in createDelegate below.
alert('Hi, ' + name + '. You clicked the "' + this.text + '" button.');
}
var btn = new Ext.Button({
text: 'Say Hi',
renderTo: Ext.getBody()
});
// This callback will execute in the scope of the
// button instance. Clicking the button alerts
// "Hi, Fred. You clicked the "Say Hi" button."
btn.on('click', sayHi.createDelegate(btn, ['Fred']));
</code></pre>
* @param {Object} obj (optional) The object for which the scope is set
* @param {Array} args (optional) Overrides arguments for the call. (Defaults to the arguments passed by the caller)
* @param {Boolean/Number} appendArgs (optional) if True args are appended to call args instead of overriding,
* if a number the args are inserted at the specified position
* @return {Function} The new function
*/
createDelegate : function(obj, args, appendArgs){
var method = this;
return function() {
var callArgs = args || arguments;
if (appendArgs === true){
callArgs = Array.prototype.slice.call(arguments, 0);
callArgs = callArgs.concat(args);
}else if (typeof appendArgs == "number"){
callArgs = Array.prototype.slice.call(arguments, 0); // copy arguments first
var applyArgs = [appendArgs, 0].concat(args); // create method call params
Array.prototype.splice.apply(callArgs, applyArgs); // splice them in
}
return method.apply(obj || window, callArgs);
};
},
/**
* Calls this function after the number of millseconds specified, optionally in a specific scope. Example usage:
* <pre><code>
var sayHi = function(name){
alert('Hi, ' + name);
}
// executes immediately:
sayHi('Fred');
// executes after 2 seconds:
sayHi.defer(2000, this, ['Fred']);
// this syntax is sometimes useful for deferring
// execution of an anonymous function:
(function(){
alert('Anonymous');
}).defer(100);
</code></pre>
* @param {Number} millis The number of milliseconds for the setTimeout call (if 0 the function is executed immediately)
* @param {Object} obj (optional) The object for which the scope is set
* @param {Array} args (optional) Overrides arguments for the call. (Defaults to the arguments passed by the caller)
* @param {Boolean/Number} appendArgs (optional) if True args are appended to call args instead of overriding,
* if a number the args are inserted at the specified position
* @return {Number} The timeout id that can be used with clearTimeout
*/
defer : function(millis, obj, args, appendArgs){
var fn = this.createDelegate(obj, args, appendArgs);
if(millis){
return setTimeout(fn, millis);
}
fn();
return 0;
}
});