Why some using '?.' to access the JSON objects?

Question

Example:

const genre = {
  "action": {
    "rating": "8",
    "movie": "John Wick"
  },
  "romance": {
    "rating": "6.5",
    "movie": "The Girl Next door"
  }
}

For accessing the movies based on the 'Genre' we can use genre.action

But why genre?.action also works. Can anyone explain I've seen people use this '?.' to access the JSON objects.

Thanks:)

Voting to close - duplicate of [Null-safe property access (and conditional assignment) in ES6/2015](https://stackoverflow.com/questions/32139078/null-safe-property-access-and-conditional-assignment-in-es6-2015) — esqew, Aug 02 '21 at 15:01

score 2 · Accepted Answer · edited Aug 02 '21 at 15:11

2

This is call Optional chaining which allows to access the key of the nested object only if the key is not nullish or undefined

const genre = {
  "action": {
    "rating": "8",
    "movie": "John Wick"
  },
  "romance": {
    "rating": "6.5",
    "movie": "The Girl Next door"
  }
}

console.log(genre.action?.rating);
console.log(genre.someKey?.someKey)

edited Aug 02 '21 at 15:11

LeeLenalee

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answered Aug 02 '21 at 15:02

brk

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And this should be a close vote and not an answer... – Andreas Aug 02 '21 at 15:06

Why some using '?.' to access the JSON objects?

1 Answers1