Answers for "in object key exists js"

16

javascript does key exist

var person={"name":"Billy","age":20}
person.hasOwnProperty("name"); // true
person.hasOwnProperty("sex"); // false
Posted by: Guest on July-22-2019
6

javascript check if key exists in object

"key" in obj // true, regardless of the actual value

If you want to check if a key doesn't exist, remember to use parenthesis:
!("key" in obj) // true if "key" doesn't exist in object
!"key" in obj   // ERROR!
Posted by: Guest on October-01-2020

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