Python 3 incorporated types into the language itself, in a similar way (though non-reified) to PHP. This seems much easier to deal with than requiring two files (.rb and .rbs) to describe a single data structure.
TypeScript hasn't ever done anything for me than give me 3rd party dependency integration headaches. I love strongly typed languages and compile time checking, but TypeScript has never seemed worth the trade off due to its broken interoperability with normal JavaScript and the terrible state of crowd sourced typedefs. I'm either fighting some badly defined third party typedef, spending a lot of time creating typedefs myself or dealing with a version issue because the typedef isn't compatible with the version of the library I'm using.
When I use JavaScript I hardly ever run into issues that static typing would have prevented and I have zero TypeScript issues.
Honestly how has it improved the speed at which you get things done? Were you just constantly running into JavaScript bugs due to the lack of typing?
Honestly, I rarely refer to documentation for these things because every project is a snowflake and the documentation gradient goes from no documentation to perfect documentation. By that, I don't just mean the words, I mean the website or the framework used to document, as well as the style of documentation (more like flavor?) Typescript is the great equalizer that makes a project with no documentation (but decent comments or method/var names) just as documented as one that that does.
I can also ctrl-space easy to get a list of methods in case I forgot which method I needed, or if I want to discover what's available. That's enormous in my style of programming. Sure beats going to someone else's documentation page, trying to read it.
Some of the improvement is not necessarily that I have javascript bugs due to lack of typing but rather that with typescript I don't get those bugs which means I don't have to reason about avoiding those bugs anymore like I did with javascript. Sort of a reduced cognitive load.
Also, I have a few coworkers that are not javascript/typescrpt savvy that I was able to get up to speed with typescript fairly easily due to the easy of using the types. There are, of course, hard things such as partials or understanding tsconfig.json or even generating types that I don't cover with them and just have them come and get me when they're ready.
For most things without types I just do the declare module in a d.ts - however, I will first try to find another package that does the same thing with types. Most popular packages these days do include types, some better than others.
After I re-read above, I realized that a lot of it depends on the IDE. If I were still using vim or kate/gedit, it probably wouldn't be a huge timesaver. Fortunately, I settled on one of the intellij editors.