Null [object Object]

RaceProUK

Continuing the discussion from History of Avatar History (complete with @accalia's swappable heads):

Something went weird then @abarker edited his post:

abarker

@RaceProUK said:

Something went weird then @abarker ~~edited~~replied to his post:

FTFY

Onyx

SSTPFY

accalia

whey did i get an @mention for that post?

RaceProUK

@accalia said:

whey did i get an @mention for that post?

Maybe from the inadvertent @mention in the link?
@RaceProUK said:

Continuing the discussion from History of Avatar History (complete with @accalia's swappable heads):

Onyx

And I just realized we screenshotted two different bugs: null [Object object] as number of replies originally, and another null [Object object] as the text of the linked topic in my screenshot.

Pointing this out for anyone else as blind as me.

Yamikuronue

...seriously blind

NOT_A_BUG THREAD_TITLE

Onyx

Desk. Head. Sleep required.

ben_lubar

!LikeBot r null [object Object]

LikeBot

Remembered 'null' as "[object Object]".

tar

[object Object] is what Javascript thinks is a sensible way to convert an object into a string.

ben_lubar

null is null or not an object.

tar

@ben_lubar said:

null is null or not an object.

Yes.

darkmatter

Unless you're in database land, where null is not equal to any object, but it's also not not equal to any object either. Nor is it even equal to itself. It simply is.

[code]
select object from (select 1 as object) where null <> object

0 rows

select object from (select 1 as object) where null = object

0 rows

select object from (select 1 as object) where null = null

0 rows

select object from (select 1 as object) where null is null

1 row [1]
[/code]

ben_lubar

typeof null === 'object'

darkmatter

had to clarify myself with a mega-edit. my initial flippant remark was too far off base to leave standing.

tar

function realTypeOf(obj) {
    return Object.prototype.toString.call(obj).slice(8, -1);
};

Filed under: Javascript is amazing!

ben_lubar

Nope, that doesn't work either.

Object.prototype.toString.call(new function Potato(){}).slice(8, -1);
 -> Object

tar

Uhhh, I don't know what to tell you (other than 'you done fucked it up'...):

C:\>node
> function realTypeOf(obj) {
...     return Object.prototype.toString.call(obj).slice(8, -1);
... };
undefined
> realTypeOf(function() {})
'Function'
>

darkmatter

a new function is an object.
[code]
Object.prototype.toString.call(function Potato(){}).slice(8, -1);

"Function"[/code]

tar

Ooh, my assertion holds :D

darkmatter

the difference between what you two did, put in longer form is this:
[code]
var a = function Potato(){};
Object.prototype.toString.call(a).slice(8, -1);

"Function"

Object.prototype.toString.call(new a).slice(8, -1);

"Object"

Object.prototype.toString.call(null).slice(8, -1);

"Null"
[/code]

Filed Under: How the fuck do you add blank lines in a code block....

riking

    Use a different code block delimiter, that's how.

    Note that four spaces is the only way to talk about triple backticks.
    ```

darkmatter

@riking said:

Note that four spaces is the only way to talk about triple backticks.

Fail. The first rule of triple backticks is, "Don't talk about triple backticks."

tar


like

this

(<code> inside <pre>) or

like

this

Just not like this:

[code]
Here's

your

problem
[/code]

darkmatter

or i could have done
here is some code

here is some code

or

here is some code

here is some code

to get a code-color background on the blank line.

but i did not want to do such retarded shit.
i just wanted a fucking [code] block that prints what it has in it.

darkmatter

Also, interesting that <pre> in a <code> kills the background color

and that blakeyrat's law continues to hold - even topics about a dicsourse bug degenerate into complaints about other dicsourse annoyances.

tar

@darkmatter said:

retarded shit

A mixture of at least three different formatting systems, all of which have slightly different appearances.

int main()

[code]{[/code]

    printf("Today I learned how to truly hate.\n")</pre
    printf("Now I am at peace.\n")


[code]    worst[worst]++;[/code]

        return DO_NOT_LOOK_AT_THE_RAW;
}

tar



int main() {

return "I think I'll just look at the page source for reference "

"and build my HTML directly in the future" + 1;

}

ben_lubar

Except that calling the new operator on a function value constructs a new instance of that type. String is a function, new String is a String object.

tar

This post is deleted!

tar

@darkmatter said:

Also, interesting that <pre> in a <code> kills the background color

That was bugging me— AFAICT, it's omitting the > from a </pre> tag which causes the next set of <code><pre> to be messed up with no background colour...

no background

no background

no background

no background

Half-formed tags are their own special kind of formatting in Discourse...

EDIT: and of course, never trust the preview window either...

darkmatter

@ben_lubar said:

Except that calling the new operator on a function value constructs a new instance of that type. String is a function, new String is a String object.

Which is exactly what I just said? the new a; in my code yields the same result as the new function Potato(){} in your code...

[code]
new function Potato(){};

Potato {}[/code]
[code]
var b = new function Potato(){};b;
Potato {}[/code]
[code]
var a = function Potato(){};new a;
Potato {}[/code]
[code]
var a = function Potato(){};var b = new a();b;
Potato {}[/code]

ben_lubar

@darkmatter said:

var a = function Potato(){};
Object.prototype.toString.call(a).slice(8, -1);
>"Function"
Object.prototype.toString.call(new a).slice(8, -1);
>"Object"

?

darkmatter

I fail to get what you are getting at...
unless you're struggling with my not having redeclared var a = function Potato(){}; since it carries over in the chrome console i'm testing in.

basically,
new function Potato(){};
yields the same result as
var a = function Potato(){};new a;
--scratch that last one.. wrong pasta

They all make a Potato object.

ben_lubar

@darkmatter said:

They all make a Potato object.

Yes, and as I said in the post that started this conversation:

@ben_lubar said:

Nope, that doesn't work either.

Object.prototype.toString.call(new function Potato(){}).slice(8, -1);
 -&gt; Object
```</blockquote>

The code @tar wrote returns "Object" when it should return "Potato".

tar

@ben_lubar said:

The code @tar wrote returns "Object" when it should return "Potato".

No, that's the code you wrote, which is wrong and broken as @darkmatter explained.

darkmatter

Because there's no such thing as a Potato type? There is a Potato Object, which it correctly identifies as an Object, because it is.

ben_lubar

Why can I have [object Number] or [object String] but not [object Potato]?

darkmatter

Because the point of his code is to print whether something is an Object, Function, Null, etc.... not a Potato or a Witch or a Deskjockey
[code]Object.prototype.toString.call(null).slice(8, -1);

"Null"[/code]
[code]
Object.prototype.toString.call(function(){}).slice(8, -1);
"Function"[/code]
[code]Object.prototype.toString.call(new function(){}).slice(8, -1);
"Object"[/code]

ben_lubar

Object.prototype.toString.call(new String()).slice(8, -1);
"String"
Object.prototype.toString.call(new Number()).slice(8, -1);
"Number"
Object.prototype.toString.call(new Function()).slice(8, -1);
"Function"
Object.prototype.toString.call(new Image()).slice(8, -1);
"HTMLImageElement"
Object.prototype.toString.call(new null()).slice(8, -1);
Uncaught TypeError: object is not a function

tar

> new null()
TypeError: object is not a function
    at repl:1:2
    at REPLServer.self.eval (repl.js:110:21)
    at Interface.<anonymous> (repl.js:239:12)
    at Interface.emit (events.js:95:17)
    at Interface._onLine (readline.js:203:10)
    at Interface._line (readline.js:532:8)
    at Interface._ttyWrite (readline.js:761:14)
    at ReadStream.onkeypress (readline.js:100:10)
    at ReadStream.emit (events.js:98:17)
    at emitKey (readline.js:1096:12)
>

ben_lubar

So Object.prototype.toString.call(null).slice(8, -1); should return Object, then, since null is object.

darkmatter

Yeah, I don't get what your point is. It's taking the [object Number] or [object String] that you get back from the plain call to the "toString" method in the prototype and pulling off the end piece of that coerced to string to return as the "Type". That method doesn't extend the functionality in any fashion to return the other non-native types natively.

[code]
var a = function Potato(){};a.prototype = { };
a.prototype

Object { }[/code]
[code]
String.prototype
String {fmt: function, w: function, loc: function, camelize: function, decamelize: function…}
[/code]

darkmatter

Note: Starting in JavaScript 1.8.5 toString() called on null returns [object Null], and undefined returns [object Undefined]

darkmatter

you can override the toString on an object to get your type back....
[code]
function Potato(){};Potato.prototype.toString = function(){ return "[object Potato]"; }
(new Potato).toString();

"[object Potato]"
[/code]
but it won't help the base object's toString() call to recognize it...
[code]
Object.prototype.toString.call(new Potato);
"[object Object]"
[/code]
[code]
Potato.prototype.toString.call(new Potato());
"[object Potato]"
[/code]
also, since i hardwired the Potato object's toString:
[code]Potato.prototype.toString.call(null);
"[object Potato]"[/code]

I suppose that if you expected your new Object type to be returned natively, it would be broken?

to be fair,
[code]Potato.prototype

Potato {toString: function}[/code]
so you'd think that "Potato" could be obtained!

tar

I don't expect that this is going to help at all, but here's where that realTypeOf() function came from, and the rationale behind it...

Javascript: A Better typeof -- Accurately Determine the Type of Variable (Array, String, Boolean, Number, Function, etc.)

http://bonsaiden.github.io/JavaScript-Garden/#types.typeof

The typeof operator... is probably the biggest design flaw of JavaScript, as it is almost completely broken.

darkmatter

I think that is why I didn't see what @ben_lubar was getting at... because I thought it was just replacing "typeof" for more object native cases - returning the XXXX from when you get "[object XXXX]" as output from toString() - instead of always returning "object" for all objects, not that it was somehow trying to allow custom object type definitions.

Technically you COULD add custom object type definitions by modifying the toString in the prototype of the base Object... but that's probably not the greatest plan.

darkmatter

@darkmatter said:

Technically you COULD add custom object type definitions by modifying the toString in the prototype of the base Object... but that's probably not the greatest plan.

[code]
//i just want my motherfucking potatoes.
Object.prototype.toString = function(){ return "[object Potato]"; }; Object.prototype.toString.call(new Potato).slice(8,-1);

"Potato"
[/code]

darkmatter

Annnnnnd more null bugs, dicsourse shat bricks on itself after I posted:

Had to hard refresh F5 to get it to let me post again.