Null evaluating as not equal to null

Asked May 31 '22 at 19:11

Active May 31 '22 at 19:11

Viewed 27 times

-4

Let's say we have an object with only one key value pair, where the key is null, declared using:

const myDict = { null: 'value 1'}

Why when we use the === operator to check if the key is null, JavaScript returns false?

const myDict = { null: 'value 1'}
console.log(Object.keys(myDict)[0] === null)

asked May 31 '22 at 19:11

Sam

1

The key you have specified in myDict is the string "null", not the value null. – James May 31 '22 at 19:12
3

Because the key is a string `'null'` not a `null` literal – Roberto Zvjerković May 31 '22 at 19:12
If you REALLY are attempting `null` -- It should look like `const myDict = { : 'value 1'}` which would not run anyway .. Since the JSON object is invalid at that point .. – Zak May 31 '22 at 19:14
how can we have a json object without any key? – sandeep joshi May 31 '22 at 19:15
1

@sandeepjoshi `{}` – Roberto Zvjerković May 31 '22 at 19:15
`console.log(typeof Object.keys(myDict)[0])` – mplungjan May 31 '22 at 19:16
Does this answer your question? [Can't force object keys to be integer](https://stackoverflow.com/questions/52060440/cant-force-object-keys-to-be-integer) – SuperStormer May 31 '22 at 19:16
Also related: https://stackoverflow.com/questions/3633362/is-there-any-way-to-use-a-numeric-type-as-an-object-key – SuperStormer May 31 '22 at 19:17
@Sam If you want to have a `null` literal as a key in some kind of key-value pair datastructure, you can use a `Map` – Roberto Zvjerković May 31 '22 at 19:18

0 Answers0