PyCharm and JS (Babel) are only similar in that they turn text source code into AST's
With Python + PyCharm, the default mode is to allow developers to exclude and ignore types and code will still run, no matter how many orange/red markers are in PyCharms gutter. To change that mode, you need to consciously decide to add something to your workflow that will impede you if something is wrong e.g. git hooks to run linters, flake8, black etc.
With TypeScript, the default mode is to stop the developer in their tracks - the TS compiler will fail, and you can't run code (generated JS) that doesn't exist. Types are not optional, unless you make them explicitly so (which is still providing a type).
> I don't see how types can work if no type information is provided.
TS can still import native JS code... given that it has a TypeScript declaration file [0]. Many popular libraries offer one now, but many more do not. The community came together and created DefinitelyTyped [1], where 10k contributors have made 65k commits to provide TS declaration files for over 5,200 libraries spanning countless versions/releases.
This means a TS developer can import JS code that doesn't have 1st-party TS support, but does have 3rd-party through DefinitelyTyped.
With Python + PyCharm, the default mode is to allow developers to exclude and ignore types and code will still run, no matter how many orange/red markers are in PyCharms gutter. To change that mode, you need to consciously decide to add something to your workflow that will impede you if something is wrong e.g. git hooks to run linters, flake8, black etc.
With TypeScript, the default mode is to stop the developer in their tracks - the TS compiler will fail, and you can't run code (generated JS) that doesn't exist. Types are not optional, unless you make them explicitly so (which is still providing a type).
> I don't see how types can work if no type information is provided.
TS can still import native JS code... given that it has a TypeScript declaration file [0]. Many popular libraries offer one now, but many more do not. The community came together and created DefinitelyTyped [1], where 10k contributors have made 65k commits to provide TS declaration files for over 5,200 libraries spanning countless versions/releases.
This means a TS developer can import JS code that doesn't have 1st-party TS support, but does have 3rd-party through DefinitelyTyped.
[0] https://www.typescriptlang.org/docs/handbook/declaration-fil...
[1] https://github.com/DefinitelyTyped/DefinitelyTyped