Calling dynamic function with dynamic number of parameters

Question

I   m looking for a trick about this  I know how to call a dynamic  arbitrary function in JavaScript  passing specific parameters  something like this   function mainfunc func  par1  par2       window func  par1  par2      function calledfunc par1  par2          Do stuff here    mainfunc  calledfunc    hello    bye      I know how to pass optional  unlimited parameters using the arguments collection inside mainfunc  but  I can   t figure how to send an arbitrary number of parameters to mainfunc to be sent to calledfunc dynamically  how can I accomplish something like this  but with any number of optional arguments  not using that ugly if   else    function mainfunc func       if arguments length    3          window func  arguments 1   arguments 2        else if arguments length    4          window func  arguments 1   arguments 2   arguments 3        else if arguments length    5          window func  arguments 1   arguments 2   arguments 3   arguments 4       function calledfunc1 par1  par2          Do stuff here    function calledfunc2 par1  par2  par3          Do stuff here    mainfunc  calledfunc1    hello    bye    mainfunc  calledfunc2    hello    bye    goodbye

User · Answer

Your code only works for global functions  ie  members of the window object  To use it with arbitrary functions  pass the function itself instead of its name as a string   function dispatch fn  args        fn    typeof fn     function     fn   window fn       Allow fn to be a function object or the name of a global function     return fn apply this  args             args is optional  use an empty array by default    function f1       function f2         var f   function           dispatch f   1  2  3       dispatch f1    foobar     dispatch  f1     foobar      f2        calls inner-function  f  in  f2  dispatch  f    1  2  3        doesn t work since  f  is local in  f2

User · Answer

Now I m using this   Dialoglar Confirm   function   title   question  callback OK        var confirmArguments   arguments      bootbox dialog           title    lt b gt      title     lt  b gt            message   question          buttons                success                    label   OK                   className   btn-success                   callback  function                          if  typeof callback OK      function                                callback OK apply this Array prototype slice call confirmArguments  3                                                                       danger                    label   Cancel                   className   btn-danger                   callback  function                            this  hide

User · Answer

Use the apply method of a function -  function mainfunc  func       window func  apply null  Array prototype slice call arguments  1         Edit   It occurs to me that this would be much more useful with a slight tweak -  function mainfunc  func       this func  apply this  Array prototype slice call arguments  1         This will work outside of the browser  this defaults to the global space   The use of call on mainfunc would also work -  function target a        alert a     var o         suffix    World       target  function s    alert s   this suffix         mainfunc  target    Hello     mainfunc call o   target    Hello

User · Answer

In case somebody is still looking for dynamic function call with dynamic parameters -      callFunction  aaa  hello    world           function callFunction func                    try                                       eval func                                     catch  e                                        function aaa a  b                    alert a         b

User · Answer

Couldn t you just pass the arguments array along   function mainfunc  func          remove the first argument containing the function name     arguments shift        window func  apply null  arguments      function calledfunc1 args          Do stuff here    function calledfunc2 args          Do stuff here    mainfunc  calledfunc1   hello   bye    mainfunc  calledfunc2   hello   bye   goodbye

User · Answer

function a a  b        return a   b     function call a         return a apply a  Array prototype slice call arguments  0       console log call a 1  2        console  3

User · Answer

You could use  apply    You need to specify a this    I guess you could use the this within mainfunc   function mainfunc  func        var args   new Array        for  var i   1  i  lt  arguments length  i            args push arguments i         window func  apply this  args

User · Answer

Here s what you need   function mainfunc         window Array prototype shift call arguments   apply null  arguments       The first argument is used as the function name and all of the remaining ones are used as arguments to the called function     We re able to use the shift method to return and then delete the first value from the arguments array  Note that we ve called it from the Array prototype since  strictly speaking   arguments  is not a real array and so doesn t inherit the shift method like a regular array would     You can also call the shift method like this      shift call arguments

User · Answer

The simplest way might be   var func  myDynamicFunction   myHandler  var arg1   100  arg2    abc    window func  apply null  arg1  arg2      Assuming  that target function is already attached to a  window  object

User · Answer

If you want to pass with  arguments  a few others  you have to create the array of all arguments together  i e  like this   var Log         log  function             var args     myarg here            for i 0  i lt arguments length  i    args   args concat arguments i            console log apply this  args

[javascript] Calling dynamic function with dynamic number of parameters

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