JavaScript function overloading

The JavaScript function does not support overloading. Sometimes we want to define overloaded methods like Java, C and other languages, so we can define overloaded functions in other ways. Of course, there are many ways to achieve it, and everyone may be different. Below I posted my implementation and use of the way to communicate with you.

JS Source:

/** *  function Parameter overloading method  overload, the function parameters are pattern-matched. The default dispatcher support * and ... and?, "*" denotes an arbitrary type of argument, "..." to denote multiple arguments of any  * type, "?" Generally used in ",?..." means 0 or any number of parameters  *  @method  overload *  @static  *  @param  {funcmaps }  List of functions to accept calls based on match  *  @return  {function}  overloaded functions  */var overload = { Map: function (arr, callback, pthis) &NBSP;{VAR&NBSP;LEN&NBSP;=&NBSP;ARR.LENGTH;VAR&NBSP;RLT  = new array (len);for  (var i = 0; i < len; i++)  {if  (I in arr)  rlt[i] = callback.call (Pthis, arr[i], i, arr );} Return rlt;},getobjectclassname: function (obj)  {if  (obj &&  Obj.constructor && obj.constructor.tostring ())  {var arr =  Obj.constructor.toString (). Match (/function\s* (\w+)/);if  (arr && arr.length == &NBSP;2)  {return arr[1];}} Return&nBsp;undefined;},overload: function (dispatcher, func_maps)  {if  (! ( dispatcher instanceof function))  {func_maps = dispatcher;dispatcher =  function (args)  {var ret = [];return overload.map (args, function (o)  {return  overload.getobjectclassname (o)}). Join ();}} Return function ()  {var key = dispatcher ([].slice.apply (arguments));for  (var  i in func_maps)  {var pattern = new regexp ("^"  + i.replace (" * ", " [^,]* "). Replace (" ... ", ". * ")  + " $ ");if  (Pattern.test (key))  {return  Func_maps[i].apply (this, arguments);}}};

Example:

var test = Overload.overload ({"String,string": function (b) {return a + B;}, "Number,number": function (b) {return a + B;} , "String,date": function (A, b) {return a + b.tolocalestring ();}}); Console.log (Test ("Hello", "world!")) Console.log (test) console.log (Test ("Now Time is:", new Date ()))

Result

Hello world!

3

Now time is:2016-07-14 21:07:29

Of course, custom types are also supported:

var test = Overload.overload ({"String,string": function (b) {return a + B;}, "Number,number": function (b) {return a + B;} , "String,date": function (A, b) {return a + b.tolocalestring ();}, "Student": function (s) {return ' name ' is ' +s.name+ ' and ' age ' Is "+s.age;}}); function Student (name,age) {this.name = Namethis.age = Age}console.log (Test (New Student ("Zhang San", 23)))

Result

Name is Zhang San and is 23

Of course you can also use wildcards, here is not an example.

Attention:

When calling an overloaded function argument list with the same type and number of two functions, the latter is called;

When wildcards and non-wildcard functions satisfy both conditions, the former is called in the defined order.

This article from "Tears Dream of the Red" blog, please be sure to keep this source http://wangywei.blog.51cto.com/7093660/1826527

JavaScript function overloading