Compiling Typescript to NodeJs: es6 types issues

I think i'm missing something with the typescript 2 type system when used with nodejs.

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Here is the situation:

• Compiling a small nodejs express server written in typescript to plain es5 in order to be run under node 6.10.0 (target: es5 in tsconfig.json).
• In my package.json, i installed @types/node (7.0.3) to get node's type informations.

When installing my project using npm (v3.10.10) and then compiling it with typescript (v2.1.5) i get a bunch or errors related to 'Iterable' and 'Iterator' symbol, (which are es6 symbols).

So from what i understand, @types/node use es6 types out of the box, assuming they are already availables.

In order to have the es6 types (Iterator, Iterable and so on) it seams that there is two solutions:

1. Add the core-js package.
2. Target es6 instead of es5 in tsconfig.json which will force typescript to use it's lib/lib.es2015..d.ts* definitions files.

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In my opinion, the second approach is better.

Is this the official way to go when compiling ts to node ? ie: targeting es6 in tsconfig ?

How can i be sure that the underlying node engine will effectively support those es6 features ? What if i'm using an old nodejs version without es6 support ?

I'd be glad to discuss to clearly understand the underlying mechanisms !

Thank you

via Clement