Object.prototype

The prototype of all objects (also an object itself). Anything you add to this prototype will be inherited by all other objects.

>>> var s = new String('noodles');
>>> Object.prototype.custom = 1;

1

>>> s.custom

1

constructor

Points back to Object

>>> Object.prototype.constructor === Object

true

>>> var o = new Object();
>>> o.constructor === Object

true

toString(radix)

Returns a string representation of the object. If the object happens be a Number object, then the radix parameter defines the base of the returned number. The default radix is 10.

>>> var o = {prop: 1};
>>> o.toString()

"[object Object]"

>>> var n = new Number(255);
>>> n.toString()

"255"

>>> n.toString(16)

"ff"

toLocaleString()

Same as toString() but matching the current locale. Meant to be implemented by objects such as Date() and provide locale-specific values, such as different date formatting.

valueOf()

Returns the this object itself, but for other types of objects may return a different value. For example, Number objects return a primitive number and Date objects return a timestamp.

>>> var o = {};
>>> typeof o.valueOf()

"object"

>>> var n = new Number(101);
>>> typeof n.valueOf()

"number"

>>> var d = new Date();
>>> typeof d.valueOf()

"number"

>>> d.valueOf()

1208158875493

hasOwnProperty(prop)

Returns true if a property is an own property of the object or false if it was inherited from the prototype chain. Also returns false if the property doesn't exist.

>>> var o = {prop: 1};
>>> o.hasOwnProperty('prop')

true

>>> o.hasOwnProperty('toString')

false

isPrototypeOf(obj)

Returns true if an object is used as a prototype of another object. Any object from the prototype chain can be tested, not only the direct ancestor.

>>> var s = new String('');
>>> Object.prototype.isPrototypeOf(s)

true

>>> String.prototype.isPrototypeOf(s)

true

>>> Array.prototype.isPrototypeOf(s)

false

propertyIsEnumerable

(prop)

Returns true if a property shows up in a for-in loop.

>>> var a = [1,2,3];
>>> a.propertyIsEnumerable('length')

false

>>> a.propertyIsEnumerable(0)

tru e