It allows us to define a property in an existing object using a property descriptor.
var obj = { };
Object.defineProperty(obj, 'foo', { value: 'foo' });
console.log(obj.foo);Console output
foo
Object.defineProperty can be called with the following options:
Object.defineProperty(obj, 'nameOfTheProperty', {
value: valueOfTheProperty,
writable: true, // if false, the property is read-only
configurable : true, // true means the property can be changed later
enumerable : true // true means property can be enumerated such as in a for..in loop
});Object.defineProperties allows you to define multiple properties at a time.
var obj = {};
Object.defineProperties(obj, {
property1: {
value: true,
writable: true
},
property2: {
value: 'Hello',
writable: false
}
});