Object.keys(obj) returns the name property of the object which becomes handy to enumerate the property names, in the same order as returned with a normal loop.
Input:
const myObject = { name: 'somename', age: 40, gender: 'female'};
console.log(Object.keys(myObject));
Output:
["name", "age", "gender"]
For
non-object, the return type is an empty array.
Input:
console.log(Object.keys(''));
Output:
[]
For input of array type,
it is the index of the array.
Input:
console.log(Object.keys(['hello', 'hello2']));
Output:
["0", "1"]
And for input of type
string, the output is the array of the index for characters.
Input:
console.log(Object.keys('hello2'));
Output:
["0", "1", "2", "3", "4", "5"]
Syntax:
Object.keys(obj)
Parameter:
The object of which the enumerable's own properties are to be returned.
Return value:
An array of strings representing all the enumerable properties of the given object.
Exception:
Throws exception if parameter is not a valid object i.e. null or undefined.
More at https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/keys