Chrome's Javascript console: what does it output in terms of objects? -

from javascript console in chrome:

> function person(name){this.name=name;} undefined 

at point, person.prototype should empty object according javascript specs. let's assign it:

> p=person.prototype   > person 

note that > person clickable , expands to:

constructor: function person(name){this.name=name;} __proto__: object 

but... wasn't meant empty object? stuff? if alert:

alert(p) 

you [object object]. why, when type in chrome console, come out > person expands? wasn't meant empty object?

thank you!

no, prototype has constructor property points function prototype of. , of course inherits object too, internal __proto__ property.

it defined in ecmascript 5 section 13.2, creating function objects:

(...)

16. let proto result of creating new object constructed expression new object()where object the standard built-in constructor name.

17. call [[defineownproperty]] internal method of proto arguments "constructor", property descriptor {[[value]]: f, { [[writable]]: true, [[enumerable]]: false, [[configurable]]: true}, , false.

18. call [[defineownproperty]] internal method of f arguments "prototype", property descriptor {[[value]]: proto, { [[writable]]: true, [[enumerable]]: false, [[configurable]]: false}, , false.

(...)

this means nothing else than:

create new empty object called proto (16). define property constructor on object , set value f (the function itself) (17). define property prototype on function f , set value proto.

---

if alert object, object converted string. default behaviour convert object [object object] string, unless "special" tostring method overridden.

the chrome console lists these properties because meant debugging, need information. [object object] not informative.

fwiw, empty object looks this:

you can see internal __proto__ property here. empty object always inherits default properties, not have own properties.