How to specify value for key in JSON map (in JavaScript)?

Question

I probably am using the wrong terminology here but this is what I'm trying to do. I want to create a map with a value for each key and a value for each key's object. So using this code:

var myMap = {};
var keyVal = "abc";
var objVal = "123";
myMap.keyVal = objVal;

Now what I want to return is a JSON object that looks like {"abc":"123"} but instead it returns {"keyVal":"123"}. How can I get it to use the actual variable contents for the key instead of the variable name? (or really I guess it's not using the variable at all, just treating 'keyVal' as the key name)

If key is variable and unknown, how would u access its value? — hungryMind
– hungryMind, Commented Jul 19, 2011 at 13:30

Quentin · Accepted Answer · 2011-07-19 13:28:51Z

7

Use square bracket notation:

myMap[keyVal] = objVal;

answered Jul 19, 2011 at 13:28

Quentin

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user3020489 · Accepted Answer · 2013-11-22 05:54:09Z

0

        var datajson = JSON.parse(data);
        var keyArr = Object.keys(datajson);
        for ( var i = 0; i < keyArr.length; i++) {
            var val = datajson[keyArr[i]];
            }

answered Nov 22, 2013 at 5:54

user3020489

1

1 Comment

Bhavik Shah Over a year ago

Please refer the docs for formatting an answer. It would be really helpful to you to format future answers. Better formatted answers have higher rate of acceptance.

hungryMind · Accepted Answer · 2011-07-19 16:57:31Z

-1

var keyVal = "abc";
var objVal = "123";
eval("myMap." + keyVal + "='" + objVal + "'")

An alternative, but eval is not recommended

edited Jul 19, 2011 at 16:57

answered Jul 19, 2011 at 13:33

hungryMind

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2 Comments

MooGoo Over a year ago

eval("myMap." + keyVal) probably returns undefined, and should result in an Invalid Lefthand Assignment error in the context you used it in. What you wanted to write was eval("myMap." + keyVal + '="' + objVal + '"'), but that is just as wrong for different reasons.

hungryMind Over a year ago

Oops yes eval("myMap." + keyVal + '="' + objVal + '"') is right syntax

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