JavaScript: Object.keys
Object.keys(obj)
- Return a Array of string property keys that are own and enumerable.
const obj = {"a":3, "b":4}; console.log( Object.keys(obj) ); // [ 'a', 'b' ]
The following example shows that Symbol key and non-enumerable properties are ignored.
const uu = Object.create ( Object.prototype, { "a": { value : 3, writable: true, enumerable: true, configurable: true }, "b": { value : 3, writable: true, enumerable: false, configurable: true }, [Symbol("x")]: { value : 3, writable: true, enumerable: true, configurable: true }, }); const kk = Object.keys ( uu ); console.log( kk.length === 1); // true console.log( kk[0] === "a" ); // true