/**
+ * @class Ext.Function
+ *
+ * A collection of useful static methods to deal with function callbacks
+ * @singleton
+ */
+
+Ext.Function = {
+
+ /**
+ * A very commonly used method throughout the framework. It acts as a wrapper around another method
+ * which originally accepts 2 arguments for <code>name</code> and <code>value</code>.
+ * The wrapped function then allows "flexible" value setting of either:
+ *
+ * <ul>
+ * <li><code>name</code> and <code>value</code> as 2 arguments</li>
+ * <li>one single object argument with multiple key - value pairs</li>
+ * </ul>
+ *
+ * For example:
+ * <pre><code>
+var setValue = Ext.Function.flexSetter(function(name, value) {
+ this[name] = value;
+});
+
+// Afterwards
+// Setting a single name - value
+setValue('name1', 'value1');
+
+// Settings multiple name - value pairs
+setValue({
+ name1: 'value1',
+ name2: 'value2',
+ name3: 'value3'
+});
+ * </code></pre>
+ * @param {Function} setter
+ * @returns {Function} flexSetter
+ */
+ flexSetter: function(fn) {
+ return function(a, b) {
+ var k, i;
+
+ if (a === null) {
+ return this;
+ }
+
+ if (typeof a !== 'string') {
+ for (k in a) {
+ if (a.hasOwnProperty(k)) {
+ fn.call(this, k, a[k]);
+ }
+ }
+
+ if (Ext.enumerables) {
+ for (i = Ext.enumerables.length; i--;) {
+ k = Ext.enumerables[i];
+ if (a.hasOwnProperty(k)) {
+ fn.call(this, k, a[k]);
+ }
+ }
+ }
+ } else {
+ fn.call(this, a, b);
+ }
+
+ return this;
+ };
+ },
+
+ /**
+ * Create a new function from the provided <code>fn</code>, change <code>this</code> to the provided scope, optionally
+ * overrides arguments for the call. (Defaults to the arguments passed by the caller)
+ *
+ * @param {Function} fn The function to delegate.
+ * @param {Object} scope (optional) The scope (<code><b>this</b></code> reference) in which the function is executed.
+ * <b>If omitted, defaults to the browser window.</b>
+ * @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
+ */
+ bind: function(fn, scope, args, appendArgs) {
+ var method = fn,
+ applyArgs;
+
+ return function() {
+ var callArgs = args || arguments;
+
+ if (appendArgs === true) {
+ callArgs = Array.prototype.slice.call(arguments, 0);
+ callArgs = callArgs.concat(args);
+ }
+ else if (Ext.isNumber(appendArgs)) {
+ callArgs = Array.prototype.slice.call(arguments, 0); // copy arguments first
+ applyArgs = [appendArgs, 0].concat(args); // create method call params
+ Array.prototype.splice.apply(callArgs, applyArgs); // splice them in
+ }
+
+ return method.apply(scope || window, callArgs);
+ };
+ },
+
+ /**
+ * Create a new function from the provided <code>fn</code>, the arguments of which are pre-set to `args`.
+ * New arguments passed to the newly created callback when it's invoked are appended after the pre-set ones.
+ * This is especially useful when creating callbacks.
+ * For example:
+ *
+ var originalFunction = function(){
+ alert(Ext.Array.from(arguments).join(' '));
+ };
+
+ var callback = Ext.Function.pass(originalFunction, ['Hello', 'World']);
+
+ callback(); // alerts 'Hello World'
+ callback('by Me'); // alerts 'Hello World by Me'
+
+ * @param {Function} fn The original function
+ * @param {Array} args The arguments to pass to new callback
+ * @param {Object} scope (optional) The scope (<code><b>this</b></code> reference) in which the function is executed.
+ * @return {Function} The new callback function
+ */
+ pass: function(fn, args, scope) {
+ if (args) {
+ args = Ext.Array.from(args);
+ }
+
+ return function() {
+ return fn.apply(scope, args.concat(Ext.Array.toArray(arguments)));
+ };
+ },
+
+ /**
+ * Create an alias to the provided method property with name <code>methodName</code> of <code>object</code>.
+ * Note that the execution scope will still be bound to the provided <code>object</code> itself.
+ *
+ * @param {Object/Function} object
+ * @param {String} methodName
+ * @return {Function} aliasFn
+ */
+ alias: function(object, methodName) {
+ return function() {
+ return object[methodName].apply(object, arguments);
+ };
+ },
+
+ /**
+ * Creates an interceptor function. The passed function 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 function 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 = Ext.Function.createInterceptor(sayHi, function(name){
+ return name == 'Brian';
+});
+
+sayHiToFriend('Fred'); // no alert
+sayHiToFriend('Brian'); // alerts "Hi, Brian"
+ </code></pre>
+ * @param {Function} origFn The original function.
+ * @param {Function} newFn The function to call before the original
+ * @param {Object} scope (optional) The scope (<code><b>this</b></code> reference) in which the passed function is executed.
+ * <b>If omitted, defaults to the scope in which the original function is called or the browser window.</b>
+ * @param {Mixed} returnValue (optional) The value to return if the passed function return false (defaults to null).
+ * @return {Function} The new function
+ */
+ createInterceptor: function(origFn, newFn, scope, returnValue) {
+ var method = origFn;
+ if (!Ext.isFunction(newFn)) {
+ return origFn;
+ }
+ else {
+ return function() {
+ var me = this,
+ args = arguments;
+ newFn.target = me;
+ newFn.method = origFn;
+ return (newFn.apply(scope || me || window, args) !== false) ? origFn.apply(me || window, args) : returnValue || null;
+ };
+ }
+ },
+
+ /**
+ * Creates a delegate (callback) which, when called, executes after a specific delay.
+ * @param {Function} fn The function which will be called on a delay when the returned function is called.
+ * Optionally, a replacement (or additional) argument list may be specified.
+ * @param {Number} delay The number of milliseconds to defer execution by whenever called.
+ * @param {Object} scope (optional) The scope (<code>this</code> reference) used by the function at execution time.
+ * @param {Array} args (optional) Override 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} A function which, when called, executes the original function after the specified delay.
+ */
+ createDelayed: function(fn, delay, scope, args, appendArgs) {
+ if (scope || args) {
+ fn = Ext.Function.bind(fn, scope, args, appendArgs);
+ }
+ return function() {
+ var me = this;
+ setTimeout(function() {
+ fn.apply(me, arguments);
+ }, delay);
+ };
+ },
+
+ /**
+ * 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:
+Ext.Function.defer(sayHi, 2000, this, ['Fred']);
+
+// this syntax is sometimes useful for deferring
+// execution of an anonymous function:
+Ext.Function.defer(function(){
+ alert('Anonymous');
+}, 100);
+ </code></pre>
+ * @param {Function} fn The function to defer.
+ * @param {Number} millis The number of milliseconds for the setTimeout call (if less than or equal to 0 the function is executed immediately)
+ * @param {Object} scope (optional) The scope (<code><b>this</b></code> reference) in which the function is executed.
+ * <b>If omitted, defaults to the browser window.</b>
+ * @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(fn, millis, obj, args, appendArgs) {
+ fn = Ext.Function.bind(fn, obj, args, appendArgs);
+ if (millis > 0) {
+ return setTimeout(fn, millis);
+ }
+ fn();
+ return 0;
+ },
+
+ /**
+ * Create a combined function call sequence of the original function + the passed function.
+ * The resulting function returns the results of the original function.
+ * The passed function 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"
+
+var sayGoodbye = Ext.Function.createSequence(sayHi, function(name){
+ alert('Bye, ' + name);
+});
+
+sayGoodbye('Fred'); // both alerts show
+ * </code></pre>
+ *
+ * @param {Function} origFn The original function.
+ * @param {Function} newFn The function to sequence
+ * @param {Object} scope (optional) The scope (this reference) in which the passed function is executed.
+ * If omitted, defaults to the scope in which the original function is called or the browser window.
+ * @return {Function} The new function
+ */
+ createSequence: function(origFn, newFn, scope) {
+ if (!Ext.isFunction(newFn)) {
+ return origFn;
+ }
+ else {
+ return function() {
+ var retval = origFn.apply(this || window, arguments);
+ newFn.apply(scope || this || window, arguments);
+ return retval;
+ };
+ }
+ },
+
+ /**
+ * <p>Creates a delegate function, optionally with a bound scope which, when called, buffers
+ * the execution of the passed function for the configured number of milliseconds.
+ * If called again within that period, the impending invocation will be canceled, and the
+ * timeout period will begin again.</p>
+ *
+ * @param {Function} fn The function to invoke on a buffered timer.
+ * @param {Number} buffer The number of milliseconds by which to buffer the invocation of the
+ * function.
+ * @param {Object} scope (optional) The scope (<code><b>this</b></code> reference) in which
+ * the passed function is executed. If omitted, defaults to the scope specified by the caller.
+ * @param {Array} args (optional) Override arguments for the call. Defaults to the arguments
+ * passed by the caller.
+ * @return {Function} A function which invokes the passed function after buffering for the specified time.
+ */
+ createBuffered: function(fn, buffer, scope, args) {
+ return function(){
+ var timerId;
+ return function() {
+ var me = this;
+ if (timerId) {
+ clearInterval(timerId);
+ timerId = null;
+ }
+ timerId = setTimeout(function(){
+ fn.apply(scope || me, args || arguments);
+ }, buffer);
+ };
+ }();
+ },
+
+ /**
+ * <p>Creates a throttled version of the passed function which, when called repeatedly and
+ * rapidly, invokes the passed function only after a certain interval has elapsed since the
+ * previous invocation.</p>
+ *
+ * <p>This is useful for wrapping functions which may be called repeatedly, such as
+ * a handler of a mouse move event when the processing is expensive.</p>
+ *
+ * @param fn {Function} The function to execute at a regular time interval.
+ * @param interval {Number} The interval <b>in milliseconds</b> on which the passed function is executed.
+ * @param scope (optional) The scope (<code><b>this</b></code> reference) in which
+ * the passed function is executed. If omitted, defaults to the scope specified by the caller.
+ * @returns {Function} A function which invokes the passed function at the specified interval.
+ */
+ createThrottled: function(fn, interval, scope) {
+ var lastCallTime, elapsed, lastArgs, timer, execute = function() {
+ fn.apply(scope || this, lastArgs);
+ lastCallTime = new Date().getTime();
+ };
+
+ return function() {
+ elapsed = new Date().getTime() - lastCallTime;
+ lastArgs = arguments;
+
+ clearTimeout(timer);
+ if (!lastCallTime || (elapsed >= interval)) {
+ execute();
+ } else {
+ timer = setTimeout(execute, interval - elapsed);
+ }
+ };
+ }
+};
+
+/**
+ * Shorthand for {@link Ext.Function#defer}
+ * @member Ext
+ * @method defer
+ */
+Ext.defer = Ext.Function.alias(Ext.Function, 'defer');
+
+/**
+ * Shorthand for {@link Ext.Function#pass}
+ * @member Ext
+ * @method pass
+ */
+Ext.pass = Ext.Function.alias(Ext.Function, 'pass');
+
+/**
+ * Shorthand for {@link Ext.Function#bind}
+ * @member Ext
+ * @method bind
+ */
+Ext.bind = Ext.Function.alias(Ext.Function, 'bind');
+