Skip to main content

JavaScript: Flexible Arguments

In many use-cases it's very useful to know total number of in-parameter and there type of param.

function testArgs(){
 var args = arguments,
 param = args[0],
 type =;
 console.log('total number of in param: '+args.length);
 console.log('type of first param: '+type);
-> testArgs('test');
//total number of in param: 1
//type of first param: [object String]
-> testArgs(3, 3);
//total number of in param: 2
//type of first param: [object Number]

Above function will print the number of parameter pass to it and first parameter type.
Jquery use this trick to deal with optional parameter (like. jQuery.extend, jQuery.when etc.)

Few more example on this concept.
##Add function with flexible argument
function add(){
 var total = 0,
  arg = arguments;
 for(var i =0; i< arg.length; i++){
  total += arg[i];
 return total;
->add(1, 2, 5, 22); //ans: 30
->add(1, 2); //ans: 3

##find n highest number from the array
function highest(){ 
 function makeArray(array){ 
  //Arrays have .slice and .splice methods which return new arrays.
  return Array() array );
 return makeArray(arguments).slice(1).sort(function(a,b){ 
  return b - a; 
->highest(1, 1, 2, 3)[0]; //1st highest ans: 3
->highest(3, 1, 2, 3, 4, 5)[1]; //2nd highest ans: 4

John Resig wrote a function for method overloading and he is using "arguments.length" to identify which function have to call
link of original post
// addMethod - By John Resig (MIT Licensed)
function addMethod(object, name, fn){
    var old = object[ name ];
    object[ name ] = function(){
        if ( fn.length == arguments.length )
            return fn.apply( this, arguments );
        else if ( typeof old == 'function' )
            return old.apply( this, arguments );

//how to use it with function
function Users(){
  addMethod(this, "find", function(){
    // Find all users...
  addMethod(this, "find", function(name){
    // Find a user by name
  addMethod(this, "find", function(first, last){
    // Find a user by first and last name

//how to use with object prototype
function Users(){}
addMethod(Users.prototype, "find", function(){
  // Find all users...
addMethod(Users.prototype, "find", function(name){
  // Find a user by name
addMethod(Users.prototype, "find", function(first, last){
  // Find a user by first and last name


Popular posts from this blog

ERROR: Ignored call to 'alert()'. The document is sandboxed, and the 'allow-modals' keyword is not set.

Recently I found this issue while writing code snippet in "JSFiddle". And after searching, found this was happening because of new feature added in "Chrome 46+". But at the same time Chrome doesn't have support for "allow-modals" property in "sandbox" attribute.

Chromium issue for above behavior:

To make it work you have to add "allow-scripts allow-modals" in "sandbox" attribute, and use "window.alert" instead of "alert".

<!-- Sandbox frame will execute javascript and show modal dialogs --> <iframe sandbox="allow-scripts allow-modals" src="iframe.html"> </iframe>

Feature added: Block modal dialog inside a sandboxed iframe.

Feature working Demo page:

JavaScript [ExtJs3]: EditorGridPanel Read-Only (dynamically)

Many time we face the scenerio where we have to make the editor grid read-only dynamically.

Ext.override(Ext.ux.grid.CheckColumn, { editable: true, onMouseDown: function (e, t) { if ( { e.stopEvent(); var me = this, grid = me.grid, view = grid.getView(), index = view.findRowIndex(t), colindex = view.findCellIndex(t), record =; if (!grid.isReadOnly && grid.colModel.isCellEditable(colindex, index)) { record.set(me.dataIndex, ![me.dataIndex]); } } } }); var grid = new Ext.grid.EditorGridPanel({ ... isReadOnly: true, //set to flag to make check column readonly ... }); //to make other column readonly grid.on('beforeedit', function () { return false; });

JavaScript [ExtJs3]: Total “Record” count in filtered store

There is two way to get record count from the Store
store.getTotalCount() This function depend on server response value. For accuracy of the value, property shell if return by the server.

Property name for the diff. reader:
totalProperty for JsonReader, totalRecords for XmlReaderstore.getCount() Will return you the number of record from the store.
Or if you have filter on the store, it will give you the number of filtered record.
But if you want to get the total number of record regardless filtering, Then it will be like this

var totalRecords = store.snapshot ? store.snapshot.length : store.getCount();
“snapshot” is the variable in “Store” which hold the actual data in case if you have applied a filter.