How can I call a function that is contained in a string?

Question

I have a defined function.

$scope.myFunction=function(){
 alert("works")
}

I have a variable called $scope.myVar and this contains an string that is a function.

$scope.myVar="myFunction()";

How can I call the function directly from a variable ($scope.myVar) and not from the defined function($scope.myFunction)?

something like:

$scope.myVar();

this is my code..

http://jsfiddle.net/o0tuvyt2/

$scope.myFunction=function(){
 alert("works")
}

    $scope.myVar="myFunction()";

//Execute this:
//$scope.myVar() I dont know

as said in the answers, eval is a possibility.. but its unsafe and generally frowned upon to use eval unless you have a really good reason. Can you tell us more about your use case and why it has to be a string instead of just binding your variable to a function and invoking it the normal way? — James LeClair, Jan 19 '18 at 16:19

UncleDave · Answer 1 · 2018-01-19T16:19:55.753

1

You could eval it. This attempts to parse the contents of a string into executable javascript:

eval($scope.myVar);

edited Jan 19 '18 at 16:19

answered Jan 19 '18 at 16:16

UncleDave

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It's worth noting that eval is avoided in 99% of use cases because it's considered dangerous and/or a waste of resources. – zfrisch Jan 19 '18 at 16:18
1

Indeed. If at all possible you want to store references instead, for example `$scope.myVar = myFunction;` – UncleDave Jan 19 '18 at 16:18
Why you shouldn't use eval() : https://stackoverflow.com/a/86580/7415107 – André DS Jan 19 '18 at 16:22

zfrisch · Answer 2 · 2018-01-19T16:27:56.060

People tend to jump to eval, but the Function constructor is typically a better solution.

Either way there is probably a better solution overall within your use case. Evaluating JS from a string is typically a no-no except in the case of templating. Before implementing anything I would suggest looking at the situation you're trying to solve and try hard to look at it differently. Often times the first step to a better solution is realizing that you can look at a problem from a different perspective.

$scope = {};
$scope.myFunction=function(){
 alert("works")
}

    $scope.myVar= new Function("$scope.myFunction()")();

André DS · Answer 3 · 2018-01-19T17:41:37.363

0

You can use window context to call your function :

window[$scope.myVar](arguments);

Don't use eval. It's very unsafe.

Full working example (with arguments and scope) :

$scope = {};
$scope.myFunction=function(text){
 alert(text);
}

$scope.myVar="myFunction";
$scope.myArgs="great job";


$scope[$scope.myVar]($scope.myArgs);

More details here : https://stackoverflow.com/a/359910/7415107

edited Jan 19 '18 at 17:41

answered Jan 19 '18 at 16:21

André DS

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This will work if `$scope.myVar` is `"myFunction"`, not `"myFunction()"` – luisenrike Jan 19 '18 at 16:22
Then just remove parentheses : $scope.myVar = $scope.myVar.replace(/[{()}]/g, ''); – André DS Jan 19 '18 at 16:24
What if it has arguments inside? – luisenrike Jan 19 '18 at 16:24
Yeah, but I'm guessing that's not the only function he's going to use. – luisenrike Jan 19 '18 at 16:26
Here https://stackoverflow.com/a/359910/7415107, there is a full function to do it with arguments, but it don't have to be into the string – André DS Jan 19 '18 at 16:27
this not works for me.. can you put this in a snipped please? – yavg Jan 19 '18 at 16:59
Yes in few minutes – André DS Jan 19 '18 at 16:59
Here it is @yavg – André DS Jan 19 '18 at 17:44

score 0 · Answer 4 · answered Jan 19 '18 at 16:23

0

Similar question to this has already been posted.

Calling a JavaScript function named in a variable

If you read through this post you will see why you should not use eval.

answered Jan 19 '18 at 16:23

Chris

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luisenrike · Answer 5 · 2018-01-19T16:30:52.993

0

As everybody said, eval is very unsafe, but, if you really need to use it, it would be better if you use the angular version because it will evaluate your expression on the current $scope.

$scope.$eval($scope.myVar)

https://docs.angularjs.org/api/ng/type/$rootScope.Scope#$eval

edited Jan 19 '18 at 16:30

answered Jan 19 '18 at 16:23

luisenrike

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How can I call a function that is contained in a string?

5 Answers5