Object.getOwnPropertyNames()
The Object.getOwnPropertyNames() method returns an array of all properties (enumerable or not) found directly upon a given object.
Syntax
Object.getOwnPropertyNames(obj)Parameters
obj
The object whose enumerable and non-enumerable own properties are to be returned.
Description
Object.getOwnPropertyNames() returns an array whose elements are strings corresponding to the enumerable and non-enumerable properties found directly upon object. The ordering of the enumerable properties in the array is consistent with the ordering exposed by a for...in loop (or by Object.keys()) over the properties of the object. The ordering of the non-enumerable properties in the array, and among the enumerable properties, is not defined.
Examples
var arr = ['a', 'b', 'c'];
console.log(Object.getOwnPropertyNames(arr).sort()); // logs '0,1,2,length'
// Array-like object
var obj = { 0: 'a', 1: 'b', 2: 'c' };
console.log(Object.getOwnPropertyNames(obj).sort()); // logs '0,1,2'
// Logging property names and values using Array.forEach
Object.getOwnPropertyNames(obj).forEach(function(val, idx, array) {
console.log(val + ' -> ' + obj[val]);
});
// logs
// 0 -> a
// 1 -> b
// 2 -> c
// non-enumerable property
var my_obj = Object.create({}, {
getFoo: {
value: function() { return this.foo; },
enumerable: false
}
});
my_obj.foo = 1;
console.log(Object.getOwnPropertyNames(my_obj).sort()); // logs 'foo,getFoo'function Pasta(grain, size, shape) {
this.grain = grain;
this.size = size;
this.shape = shape;
}
var spaghetti = new Pasta("wheat", 2, "circle");
var names = Object.getOwnPropertyNames(spaghetti).filter(CheckKey);
document.write(names);
// Check whether the first character of a string is 's'.
function CheckKey(value) {
var firstChar = value.substr(0, 1);
if (firstChar.toLowerCase() == 's')
return true;
else
return false;
}
// Output:
// size,shape