Properly wrapping functions in JavaScript

Question

I have the following problem:

I have a function

workspace.func = function() {console.log(5);}

I attach it as an event handler:

$(workspace).bind("ping", workspace.func);

Then, I change the function definition:

var cF = workspace.func;
workspace.func = function() {
   ...
   cf.call(this);
}

but

$(workspace).trigger("ping")
>>5

How can I properly wrap the function at runtime, so that the handler points to the changed one as well?

jfriend00 · Accepted Answer · 2012-01-04 08:15:50Z

2

You can do it like this:

workspace.func = function() {console.log(5);}
$(workspace).bind("ping", function() {workspace.func()});

var cF = workspace.func;
workspace.func = function() {
   ...
   cf.call(this);
}

After reassigning the value of workspace.func, the ping event handler will go to the new function because it gets the function pointer from the variable and then executes it so if you change which function that variable points to, it will pick up the new value - unlike your original version which had a reference to the actual function so changing the workspace.func variable didn't do anything.

answered Jan 4, 2012 at 8:15

jfriend00

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1 Comment

vgru Over a year ago

+1 Alternatively, you can have workspace.func wrap a different mmber function call, and reassign that function instead of workspace.func.

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