IDE support?

François REMY fremycompany_pub at
Mon Sep 12 13:31:17 PDT 2011

Types are not only "desirable" to borrow concepts from current IDEs. We know 
from DotNET that a language running in a VM can be pretty fast, close to a 
native language. But it has to be simple for the computer. JavaScript is 
simple for the developer, but sometimes its flexibility makes it impossible 
to "optimize" code properly. And it makes JavaScript slower.

Or, to be exact, it doesn't allow to make 95% of our code faster because it 
would break the other 5%. The more a compiler understand what you're doing, 
the more it will be confident that optimizing is safe. Types may be part of 
the data a compiler may use. It doesn't need to be the only one, but it can 
be a very important one.

At a time where optimization, fluidity and speed are in everyone's mouth, it 
may be worth considering the addition of types in ECMAScript. DotNET has 
shown that you can continue to mix strongly and dynamicly types in the same 
code and that it can work seamlessy.

In ES6, "with" and indirect eval will be prohibited, and direct eval will 
not be able to create new variables in the current scope. That's huge. We're 
losing features, but it will allow a new range of optimization that were 
impossible before. Adding types to ECMAScript can do that. If you don't want 
an optimized code, you don't need to. But giving the possibility to the 
developers to choose for a faster solution should be important to this 
Discussion Group.

-----Message d'origine----- 
From: John J Barton
Sent: Monday, September 12, 2011 9:22 PM
To: es-discuss at
Subject: Re: IDE support?

On Mon, Sep 12, 2011 at 12:00 PM,  <es-discuss-request at> wrote:

Some of the discussion on this thread amounts to "IDEs work great for
typed languages so let's make JS typed".  What if we started with
"What would be great for JavaScript developers"? Then we would not
waste a lot of time talking about static analysis.  It's the wrong

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