Javascript: Add key/value pairs in nested dict; key and value are variables

Question

I have a dictionary of the following structure:

myDict = {key1:{innerKey1:innerValue1, innerKey2:innerValue2}, key2:{},...}

Based on: How can I add a key/value pair to a JavaScript object?

I tried to add inner key/value pairs like this:

someArray=['foo','bar']
var identifier = someArray[0]
var info = someArray[1]
myDict[key1][identifier] = info;

Or like this:

myDict[key1].identifier = info;

But I get the error 'cannot set property of undefined'. I think this is due to the identifier not being defined in myDict yet, but I cannot figure out how to achieve this:

myDict = {key1:{innerkey1:innerValue1, innerKey2: innerValue2, foo:bar,...}, key2:{},...}

Please note: I know in this example the assignment of variables is not necessary. I need to figure out the concept for a bigger, more complex project and this is the minimum "non-working" example.

Thanks in advance :)

Morphyish · Accepted Answer · 2019-08-09 09:27:06Z

4

From your snippet, key1 doesn't seem to be defined.

You also want to make sure that the object is defined before trying to access it

someArray=['foo','bar']
var identifier = someArray[0]
var info = someArray[1]
if (!myDict[key1]) myDict[key1] = {};
myDict[key1][identifier] = info;

answered Aug 9, 2019 at 9:27

Morphyish

4,07210 silver badges28 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Jack Bashford · Accepted Answer · 2019-08-09 09:29:42Z

3

Bracket notation requires the key be a string:

myDict["key1"][identifier] = info;

Or just use dot notation:

myDict.key1[identifier] = info;

edited Aug 9, 2019 at 9:29

answered Aug 9, 2019 at 9:25

Jack Bashford

44.3k11 gold badges56 silver badges84 bronze badges

6 Comments

Ozgar Over a year ago

This would have been my answer too, not sure why someone thought it was bad.

Morphyish Over a year ago

key1 is probably a variable to be fair.

Jack Bashford Over a year ago

I know @Morphyish, but the fact that they have not defined it has caused the error.

BJRINT Over a year ago

Since identifier is a variable defined above myDict.key1[identifier] = info would be the correct solution

Morphyish Over a year ago

@JackBashford my own bet is on the fact that key1 has no associated value in the dict when they are trying to update its property ;D

|

Collectives™ on Stack Overflow

Javascript: Add key/value pairs in nested dict; key and value are variables

2 Answers 2

Comments

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related