Defining variables dynamically in Javascript

Question

In a situation where I have something like this code:

var variableNames=["thisMonth", "thisDay"];
var variableValues=["February", 17];

Is there any way I could go through the array and initiate variables with their corresponding values? I've tried something like

for(var i=0;i<variableNames.length;i++){
    eval("var "+variableNames[i]+"="+variableValues[i]+";");
}

But I'm not getting any reults. Is eval not able to define variables, or are there other problems that exist? Any solution would be greatly appreciated.

possible duplicate of stackoverflow.com/questions/12167800/… — Will P.
– Will P., Commented Feb 18, 2014 at 22:49
As stated above; do obj[variableNames[i]] = variableValues[i]; — Johan
– Johan, Commented Feb 18, 2014 at 22:50

advncd · Accepted Answer · 2014-02-18 22:53:47Z

1

You need to assign the variables on an object. If you want to create global variables the following code should work:

for (var i=0; i<variableNames.length; i++) {
  window[variableNames[i]] = variableValues[i];
}

//test
console.log(thisMonth); //"February"

answered Feb 18, 2014 at 22:53

advncd

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loxxy · Accepted Answer · 2014-02-18 23:03:15Z

0

Here you go. You missed a couple of quotes at "='" + variableValues[i] + "';");:

var variableNames=["thisMonth", "thisDay"];
var variableValues=["February", 17];
for(var i=0;i<variableNames.length;i++){
    eval("var "+variableNames[i]+"='"+variableValues[i]+"';");
}

With that correction however, I would warn you against using it cause it's a very wrong way of doing it.

Use Objects, as most here mention.

edited Feb 18, 2014 at 23:03

answered Feb 18, 2014 at 22:55

loxxy

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1 Comment

loxxy Over a year ago

Someone had to highlight the error. Maybe OP is just curious, or perhaps a reason for doing so. :)

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