Reflect.has

The static Reflect.has() method works like the in operator as a function.

Syntax

Reflect.has(target, propertyKey)

Parameters

target

The target object in which to look for the property.

propertyKey

The name of the property to check.

Return value

A Boolean indicating whether or not the target has the property.

Exceptions

A TypeError, if target is not an Object.

Description

The Reflect.has method allows you to check if a property is in an object. It works like the in operator as a function.

Examples

Using Reflect.has()

Reflect.has({x: 0}, 'x'); // true
Reflect.has({x: 0}, 'y'); // false

// returns true for properties in the prototype chain 
Reflect.has({x: 0}, 'toString');

// Proxy with .has() handler method
obj = new Proxy({}, {
  has(t, k) { return k.startsWith('door'); }
});
Reflect.has(obj, 'doorbell'); // true
Reflect.has(obj, 'dormitory'); // false

Specifications

Specification	Status	Comment
ECMAScript 2015 (6th Edition, ECMA-262) The definition of 'Reflect.has' in that specification.	Standard	Initial definition.
ECMAScript 2017 Draft (ECMA-262) The definition of 'Reflect.has' in that specification.	Draft

Browser compatibility

See also

• Reflect
• in operator