“Periksa apakah ada kunci dalam javascript objek” Kode Jawaban

JavaScript tidak ada

var person={"name":"Billy","age":20}
person.hasOwnProperty("name"); // true
person.hasOwnProperty("sex"); // false
Grepper

JavaScript Hashtable berisi kunci

if (obj.hasOwnProperty("key1")) {
  ...
}
Faithful Finch

JavaScript Periksa apakah kunci ada di objek

"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!  Equivalent to "false in obj"

Or, if you want to particularly test for properties of the object instance (and not inherited properties), use hasOwnProperty:
obj.hasOwnProperty("key") // true
Super Seahorse

Periksa apakah ada kunci dalam javascript objek

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

Bagaimana cara memeriksa apakah ada kunci dalam javascript objek

!("key" in obj) // true if "key" doesn't exist in object
!"key" in obj   // ERROR!  Equivalent to "false in obj"
Dizzy Dugong

Memeriksa apakah ada kunci dalam objek JavaScript?

5003

Checking for undefined-ness is not an accurate way of testing whether a key exists. What if the key exists but the value is actually undefined?

var obj = { key: undefined };
console.log(obj["key"] !== undefined); // false, but the key exists!
shafeeque

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