Calling a javascript function with a string?

Question

I have a function:

var greet = function (name) {
    console.log("Hi " + name);
}

If I have a string "greet('eric')" is it possible to convert it to a function call passing "eric" as argument?

score 2 · Accepted Answer · answered Apr 20 '11 at 06:10

2

eval() is your friend ! http://www.w3schools.com/jsref/jsref_eval.asp

answered Apr 20 '11 at 06:10

Elian

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Oh totally forgot eval(). Isn't it the other way around, its evil? – ajsie Apr 20 '11 at 06:12
@weng Eval is only evil if you misuse it – Peter Olson Apr 20 '11 at 06:15
2

The call of a thousand screaming virgins tearing at their flesh accompany your answer. – Zirak Apr 20 '11 at 06:15
W3Schools bashing seems to be fashionable nowadays. They may be wrong in many aspects, but in their days (w3schools started in 1999) they were a great source of information to many. Maybe they'll catch up someday. – KooiInc Apr 22 '11 at 08:00

score 2 · Answer 2 · answered Apr 20 '11 at 06:42

You, me, him her and them fWord('ing') hate eval. There's always another way.

callMethod = function(def) {
    //all the variables are function references
    var approvedMethods = {greet: greet, love: love, marry: marry, murder: murder, suicide: suicide},
        split = def.split(/\(/); //split[0] contains function name, split[1] contains (unsplit) parameters

    //replace last ) and all possible string detonators left-over
    split[1] = split[1].replace(/\)$/, '').replace(/[\'\"]/g, '').split(','); //contains list of params

    if (!approvedMethods[split[0]])
        return 'No such function.';

    approvedMethods[split[0]].apply(window, split[1]);
}
//Called like this:
callMethod("greet('eric')");

Replace window reference with whatever.

score 1 · Answer 3 · answered Apr 20 '11 at 06:12

1

I'm not sure I've understood your question correctly, but are you looking for the eval() function?

eval("greet('eric')");

answered Apr 20 '11 at 06:12

Anders Lindahl

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score 1 · Answer 4 · answered Apr 20 '11 at 06:13

1

It is as easy as typing

eval("greet('eric')");

answered Apr 20 '11 at 06:13

Peter Olson

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KooiInc · Answer 5 · 2011-04-20T07:05:42.520

1

without eval

var greet = function (name) {
      console.log("Hi " + name);
    },
    greetstr = 'greet("Eric")';

var greeter = greetstr.split('("');
window[greeter[0]]( greeter[1].replace(/\)|"/g,'') );

Bottom line 1: use eval with care
Bottom line 2: avoid constructions like this.

Just to be sure you have all possibilities @ your disposal: setTimeout(greetstr,0);
_{Mmmm, there is an eval in there somewhere ;)}

edited Apr 20 '11 at 07:05

answered Apr 20 '11 at 06:23

KooiInc

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I guess eval() indeed is my friend in this case=) – ajsie Apr 20 '11 at 06:56

Calling a javascript function with a string?

5 Answers5