alternative to eval in Javascript

Question

I have an object created which belongs to particular class.

            var schCom1 = Server.CreateObject(ArchiveProgID);

Now, this object gives call to method which is dynamically decided.

            fnName += "(";
        for (counter=0;counter<fnArgs.length;counter++)
        {
            if(counter > 0)
                fnName += ",";
            fnName += fnArgs[counter];
        }
        fnName += ")";
        writeComment("Ready to call method:" + "schCom1." + fnName);
        // according to the type of recurrance, call method
        eval("schCom1."+ fnName);

Is there any substitution possible to this eval call ?

Any Help will be valuable .

Thanks in advance.
Tazim.

possible duplicate of [Calling dynamic function with dynamic parameters in Javascript](http://stackoverflow.com/questions/676721/calling-dynamic-function-with-dynamic-parameters-in-javascript) — Ignacio Vazquez-Abrams, Nov 12 '10 at 08:39
You should use `fnName+="("+fnArgs.join(",")+")"` instead of that `for` loop. — Ben, Nov 12 '10 at 08:45

score 3 · Accepted Answer · answered Nov 12 '10 at 08:43

Provided that fnName really is a name of a method of the schCom1 object:

schCom1[fnName].apply(schCom1,fnArgs);

Basically, the apply method for function objects allow you to call the function and provide the context (parent object) and arguments. And the apply method expects function arguments to be supplied as an array, which is useful in this case.

See the documentation of the apply method for more info:

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/function/apply

there's also the call method which does something similar but expects function arguments as a regular argument list:

https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/function/call

thanx a lot . answer was really helpful for understanding the concept — Star123, Nov 12 '10 at 08:47
fnName is not the real name of function name of schCom1 . fnName = Request("fnName"). it should be schCom1[Request("fnName")].apply(schCom1,fnArgs); — Star123, Nov 12 '10 at 09:23

score 2 · Answer 2 · answered Nov 12 '10 at 08:41

2

You can use a more simpler

schCom1[fname].apply(schCom1, fnArgs)

that would replace all your code up there

answered Nov 12 '10 at 08:41

Gabi Purcaru

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1

Don't you mean `schCom1[fnName].apply`? Other than that, nice answer :) – Aistina Nov 12 '10 at 08:43
1

@Aistina yes I did, thanks ! (didn't see the bloody point there) – Gabi Purcaru Nov 12 '10 at 08:44
1

`this` points probably to a global variable in this context, it really should be `schCom1` instead – Andris Nov 12 '10 at 08:45

alternative to eval in Javascript

2 Answers2

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