Include error maps in the typescript libraries for web apis to give developers easy access to potential thrown exceptions about typescript HOT 7 CLOSED

That's kind of what I figured, but I thought I'd give it a shot anyway. At least to get some thought in this direction. Hopefully at least the readers can see the value in what this could provide in terms of type safety, hopefully one day have an official body backing something like this.

from typescript.

How is this different from #57943 and/or #13219?

from typescript.

It's different from both of those because I'm not suggesting to make any changes whatsoever to the type system. My proposal simply about supplying type maps that conform to web standards so that developers can use them how they like. It's a benign addition that would just mean people who are building result-like error handling libraries can leverage a strong and trusted up-to-date backbone for reference purposes - getting potential error types given a certain type. One use case would be that it would allow type-safe libraries to create convenient proxies around web apis.

Example, typescript would supply something like this:

/**
 * Supplies an error map for a {@link ParentNode} instance
 */
type ParentNodeErrorMap = {
  querySelector: SyntaxError
  // ... all other errors
}

And then developers can build on top of those to create their own type systems, proxies, etc.

from typescript.

I don't understand what the request on the TypeScript side is. "error map" is not a term I'm familiar with and it doesn't really turn up any search results.

from typescript.

"Error map" is just the closest way to describe what I'm trying to put forward. It's simply a utility to map a type to its associated potential error according to w3c spec. I don't have the expertise to come up with the best way to do this. All I know it requires combing through the entire w3c spec and somehow including the potential errors in some fashion that they can accessed somehow.

Example:

Section 6.4 in the selector api specifies:

If result is invalid ([SELECT], section 12), raise a SYNTAX_ERR exception ([DOM-LEVEL-3-CORE], section 1.4) and abort this algorithm.

It would be great to have a way that this error information is somehow available in typescript. This would not affecting the typing system in any way.

I was thinking of literally the simplest way, which is likely not the best way, where typescript would supply a kind of global W3CErrorMap, and a developer can go:

type querySelectorErrors = W3CErrorMap<document>['querySelector'] // would be the type of the error associated with SYNTAX_ERR

I foresee the development of type-safe proxies for standard apis.

from typescript.

If it's not going to affect the type system in some way, it can be an out-of-band artifact that people use if they are doing this kind of thing. Expanding the scope of our project to further cover investigating all the various W3C specs to produce that document doesn't seem to be something that TS is uniquely positioned to provide.

from typescript.

This issue has been marked as "Out of Scope" and has seen no recent activity. It has been automatically closed for house-keeping purposes.

from typescript.