Google I/O 2011: JavaScript Programming in the Large with Closure Tools

Michael Bolin

Most developers who have tinkered with JavaScript could not imagine writing 1,000 lines of code in such a language, let alone 100,000. Yet that is exactly what Google engineers have done using a suite of JavaScript tools named "Closure" to produce many of the most popular and sophisticated applications on the Web, such as Gmail and Google Maps.

[noli-timere-crede-tantum]

very nice, michael. I did appreciate the subtle NES references...

[SamarPanda]

Looking forward to work in a project using closure library. Pretty impressed by its advanced mode compiler and the way it minifies the code.

[TheMonk]

From the python wiki: "Python is strongly typed as the interpreter keeps track of all variables types."

Since every programming language I use (including Javascript) does this, then by this logic EVERY programming language is strongly typed.

Definitions are important, don't you think?

[lail]

Really useful video for javascript closure newbie.

[methodinsane]

The Triforce - Great Zelda reference!! And great presenter!

[TheMonk]

Depends on your definition. Saying that Python is strongly-typed because it doesn't allow operations that some 'weakly-typed' languages do isn't really enough.

For most, 'strongly-typed' is virtually equivalent to 'statically-typed' in most usages. A strongly-typed language SHOULD allow specification of parameter types for functions, which reduces the code required to validate parameters.

Can Python do that? No? Not strongly typed enough then.

[PangeaMinor]

I would actually like my code to NOT be obfuscated or illegible (up yours, "intellectual property"), so I guess I'll just not use parts of the compiler? Is that easy enough?

[xzaz]

And this is not a issue in javascript, seeing the history of Javascript.

[Hector-bjls]

Using the classification for a large application (2:30) I would put the one I'm working on as medium.
~10, 000 LOC ( so far )
1 Person
3 months ( so far )

[TheMonk]

And C# doesn't satisfy YOUR definition either:

string.Join(", ", new int[] { 1, 2, 3 }) == "1, 2, 3"

Implicit type conversion or type promotion does not mean a language IS NOT strongly typed, any more than explicit denial of specific operations DOES mean that a language IS strongly typed.

So cherry-picking specific definitions to say 'Language X is strongly typed' is not sufficient.

[HardShooter]

In javascript

"" == 0
true

This is not strongly typed

"5" + 4
54

This isn't either.

You can't do this type of stuff in Python, that's what makes it strongly-typed.

Wikipedia defines strongly typed as : "a type system is said to feature strong typing when it specifies one or more restrictions on how operations involving values of different data types can be intermixed. The opposite of strong typing is weak typing." You're free to change the definition if you're not happy with it

[knny]

"there's no good way to ensure that calculations involving people's money comes out right."

How about that?
money*=100;
/* making calculations */
money/=100;

[HardShooter]

Once again you are free to remove Python from the example list, and change it's wikipedia page

[xzaz]

It does scare me, but not anymore with Javascript :) Does it make it good? No, does it makes it wrong? I don't know..

[lennyhome]

Javascript exists only because it was capable of opening popups faster than Java.

[redstrikedn]

Great, I'm seeking those things for my awesome project >.<

[TheMonk]

Nice - and blatant - quote mining. Just as valid as my sarcastic response.

Of course it's not that simple... it seldom is. Restricting operations on disparate types already happens in Javascript, just at a level that doesn't apparently satisfy your threshold.

Now go look at "strong typing" in Wikipedia. Does Python satisfy all of the definitions given there? No, it doesn't.

Given a narrow enough focus you can justify many things. But broaden the scope and Python is NOT strongly typed.

[batbawls]

Not really convinced. The pitch was excellent, but the practice, the development cycle, seems as if it would be a pain in the ass.

[HardShooter]

BTW Java doesn't satisfy all of the definitions

[adamghanem]

@ 07:10 People find it annoying because "things" like internet explorer. HAHAH!