How to Get an Array of JavaScript Object's Own Keys?

Find out how to get an array of object's own property names in JavaScript

You can get an array of an object's own keys in JavaScript in the following ways:

Using Object.keys()

The Object.keys() method returns an array of object's own enumerable property names (excluding Symbol properties):

// ES5+
const sym1 = Symbol('a');
const sym2 = Symbol('b');

const obj = Object.create({}, {
    foo: { value: 'bar', enumerable: true },
    baz: { value: 'qux', enumerable: false },
    [sym1]: { value: 'quux', enumerable: true },
    [sym2]: { value: 'quuz', enumerable: false },
});

const keys = Object.keys(obj);

console.log(keys); // [ 'foo' ]

Using Object.getOwnPropertyNames()

The Object.getOwnPropertyNames() method returns an array of all object's own string property names (including non-enumerable properties, and excluding Symbol properties):

// ES5+
const sym1 = Symbol('a');
const sym2 = Symbol('b');

const obj = Object.create({}, {
    foo: { value: 'bar', enumerable: true },
    baz: { value: 'qux', enumerable: false },
    [sym1]: { value: 'quux', enumerable: true },
    [sym2]: { value: 'quuz', enumerable: false },
});

const keys = Object.getOwnPropertyNames(obj);

console.log(keys); // [ 'foo', 'baz' ]

Using Object.getOwnPropertySymbols()

The Object.getOwnPropertySymbols() method returns an array of object's own Symbol properties (excluding all other string properties):

// ES6+
const sym1 = Symbol('a');
const sym2 = Symbol('b');

const obj = Object.create({}, {
    foo: { value: 'bar', enumerable: true },
    baz: { value: 'qux', enumerable: false },
    [sym1]: { value: 'quux', enumerable: true },
    [sym2]: { value: 'quuz', enumerable: false },
});

const keys = Object.getOwnPropertySymbols(obj);

console.log(keys); // [Symbol(a), Symbol(b)]

Please note that all objects have no own Symbol properties initially, therefore, Object.getOwnPropertySymbols() returns an empty array (unless you explicitly set Symbol properties on an object).


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