Evolving JavaScript with TypeScript

Google Tech Talk
November 13, 2014
Presented by Anders Hejlsberg (more info below)

ABSTRACT

In this talk Anders will give an overview of TypeScript, a statically typed superset of JavaScript that compiles to plain JavaScript. TypeScript adds optional static types, classes, interfaces, and modules to JavaScript, enabling IDE productivity features such as statement completion, refactoring, and code navigation, and making it easier for teams to communicate requirements and build applications safely. The TypeScript language features an innovative structural type system that incorporates gradual typing and type inference. The TypeScript project is open-source and hosted on GitHub.

Speaker Info:

Anders Hejlsberg is a Technical Fellow in the Developer Division at Microsoft Corporation and works on Microsoft’s .NET and JavaScript development tools. He is the chief designer of the C# programming language and co-designer of the TypeScript programming language. Before joining Microsoft in 1996, Anders was a Principal Engineer at Borland International. As one of the first employees of Borland, he was the original author of Turbo Pascal and later worked as the Chief Architect of the Delphi product line. Anders studied Engineering at the Technical University of Denmark.

[hansschenker]

Just a joy to hear such a high level presentation on Javascript and Typescript.
Typescript is not a language. It is a tool for adding type annotations to Javascript, which
in turn allows for tooling like refactoring.

[mansurali]

this will make javascript Developer's life much easier. Thanks Hejlsberg

[joshuaburkholder]

TypeScript is Outstanding!  TypeScript is a superset of JavaScript.  C++ started out as a superset of C.  TypeScript uses a source-to-source compiler (TypeScript to JavaScript).  C++ started out with a source-to-source compiler (C++ to C).  If Eich is the Ritchie of the Web, then Hejlsberg is the Stroustrup.  TypeScript is the C++ of the Web!

... and this talk is also pretty good.  ;-)

[arthas]

I was looking forward to the qna session...

[catx]

Interesting. I mainly use vanilla JavaScript and CoffeeScript in projects because I found that TypeScript (and VS IDE) is a little too "heavy" for those not-so-large-scale project. But the static type checking feature is very appealing and would save lots of troubles if used in correct places. I'll definitely try it out in my next project. 

[IdolBlackIron]

Great! TypeScript has got a very revolutionary syntax!

[loweryjk]

Finally Microsoft does something useful in the web realm. Good work! Now I want to see TypeCoffeeScript!

[allesleiwand]

"Now that we know that a is an array" ...@~8:10... never thought that such a sentence could sound that funny.

[nitrinate]

Really cool, definitely looking forward to using this on future projects.

[calvinsylveste]

TypeScript is needed because people are starting to use JavaScript in areas and for purposes it was not designed to be used.  If a developer chooses not to use an existing language fit for the purpose and would prefer to use JavaScript then TypeScript will help it to be a little more fit.

[ObjectiveCoder]

Great talk! And great to see Google and Microsoft in the same room! TypeScript is really great! Let's hope TypeScript can take off inside off Google. IMHO it's superior to AtScript/Traceur. Join forces with Microsoft instead. The excuse for developing AtScript is that they want annotations and ES6-features for Angular 2.0. I think annotations would be a great idea and is a pretty small feature to implement for TypeScript and I don't see why the TypeScript-team would not agree (Anders made them for C# after all where they are used everywhere), and TypeScript will be ES6-compliant during 2015, probably before Angular 2 is released. Help Microsoft with typescript and release angular 2 with that system. That would make Angular a strong candidate against facebook react/flux/flow for next years front-end battle.

[vivekbernard]

if VSCode had been around this time, it would've been a perfect talk. Full VS is distracting in this context

[tomasd]

I was looking forward to learn more about TypeScript syntax, types, codeblocks, how ti structure app etc. Instead this talk is more or less about how Visual studio handles auto-completion of typescript project. Interesting, but honestly JetBrain IDEs could do this even without TypeScript...

[syzer]

to sum up, one may use Typescript, OR spellchecker :)

[Proculopsis]

/*
Compiler error in this sample code on TypeScript Playground:

Select "strictNullChecks" on the Options tab
*/

function strictNullChecks(delegate?: (message: string) => void) {
let state = `typeof delegate = "${typeof delegate}"`;

if (false == (typeof delegate === "function"))
alert(state);
else
delegate(state); // typeof delegate is always "function"
}


strictNullChecks();

/*
There seems to be an issue with the "strictNullChecks"
compiler option when passing an optional delegate
parameter.

The above code works correctly but the compiler reports an
"Object is possibly 'undefined'." warning for parameter
"delegate".

It seems to be checking for the reference being bracketed
by an "if" statement checking for "typeof delegate" but
ignores that the equality might be compared to "false".
*/

[syzer]

+1 for hardcore (use of/sticking with) 'cmd'

[AThagoras]

It sort of defeats the point if it allows untyped code.
IMNSHA, not having strict static typing is the biggest problem with JavaScript.

[mistriela]

If it compile to JS, so it's better to have a native support of Dart by the browsers...

It will surely bring the web development to a new frontier !

[demisx]

All good, except the Visual Studio part. Runs on Windoze only and way too heavy.

[ashlynartificia]

Great talk, but your vector length method could produce imaginary numbers :D