dynamically call local function in javascript
The private functions are local variables and not part of any object. So, the [...]
notation for accessing a property is never going to work since there is no object the private functions are properties of.
Instead, you could make two objects: private
and public
:
var public = {},
private = {};
public.publicMethod = function(number, otherarg) {
// `.apply` with a fixed array can be replaced with `.call`
private['privateMethod' + number].call(this, otherarg);
};
private.privateMethod1 = function(arg) {
//do something with arg
};
private.privateMethod2 = function(arg) {
//do something else with arg
};
return public; // expose public, but not private
You cannot get a reference to a local variable by a string. You have to add the local objects to a namespace:
(function(window,$) {
// Use "var MyObject = " instead of "MyObject = "!! Otherwise, you're assigning
// the object to the closest parent declaration of MyVar, instead of locally!
var MyObject = (function($) {
var obj = {};
var local = {}; // <-- Local namespace
obj.publicMethod = function(number,otherarg) {
local['privateMethod'+number].call(this, otherarg);
};
var privateMethod1 = local.privateMethod1 = function(arg) {
//do something with arg
};
var privateMethod2 = local.privateMethod2 = function(arg) {
//do something else with arg
};
return obj;
})($);
window.MyObject = MyObject;
})(window,jQuery);
I'm surprised that incorrect answer is marked as accepted. Actually you CAN get a reference to a local variable by a string. Just by using eval
:
(function(window,$) {
MyObject = (function($) {
var obj = {};
obj.publicMethod = function(number,otherarg) {
// Gets reference to a local variable
var method = eval('privateMethod'+number);
// Do with it whatever you want
method.apply(this,[otherarg]);
};
var privateMethod1 = function(arg) {
//do something with arg
};
var privateMethod2 = function(arg) {
//do something else with arg
};
return obj;
})($);
window.MyObject = MyObject;
})(window,jQuery);
Actually this code is very bad and in 99.9% cases you should not use eval
. But you must know how it works and what you can do with it. I myself had a few very specific cases when usage of eval
was necessary.