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0 pointsinglor11y ago0 comments

EDIT: looks like it supports type annotations similar to closure compiler's (in docs) https://github.com/facebook/flow/blob/master/tests/docblock/...

Try running an annotated file in the browser - it's simply not valid ECMAScript syntax and no JavaScript runtime will run it 'as is'.

If the code requires transformation by a compiler aware of the language semantics and syntax - it's transpiling in my book. Just like TypeScript is a superset of ECMAScript - so is Flow (in a much lighter, closer to source sense it seems).

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masklinn11y ago

> Try running an annotated file in the browser - it's simply not valid ECMAScript syntax and no JavaScript runtime will run it 'as is'.

Of course not, but the point was that it's not a different language, it simply adds type annotations. If you strip out the type annotations, it should be a valid JS file.

inglorOP11y ago

This is also true for TypeScript though. The only thing that's not directly JS in TypeScript is shims for new JS features (from ES6) not yet implemented.

masklinn11y ago

> This is also true for TypeScript though.

AFAIK none of these are valid javascript, event assuming ES6:

* class-level variables (resolved as instance variables)

* field visibility

* initializer constructors (constructor without a body automatically assigning to a field)

* enum types

That is, you can't remove type annotations (and `interface` declarations which can probably get a pass) and end up with valid JS, which seems to be what flow yields.

j / k navigate · click thread line to collapse

0 comments

masklinn11y ago

> Try running an annotated file in the browser - it's simply not valid ECMAScript syntax and no JavaScript runtime will run it 'as is'.

Of course not, but the point was that it's not a different language, it simply adds type annotations. If you strip out the type annotations, it should be a valid JS file.

inglorOP11y ago

This is also true for TypeScript though. The only thing that's not directly JS in TypeScript is shims for new JS features (from ES6) not yet implemented.

masklinn11y ago

> This is also true for TypeScript though.

AFAIK none of these are valid javascript, event assuming ES6:

* class-level variables (resolved as instance variables)

* field visibility

* initializer constructors (constructor without a body automatically assigning to a field)

* enum types

That is, you can't remove type annotations (and `interface` declarations which can probably get a pass) and end up with valid JS, which seems to be what flow yields.

j / k navigate · click thread line to collapse