Repository navigation
Better handling of untyped node module imports #11106
Description
Activity
Is there anyway we can solve this in a non npm specific manner? I like the concept but tying it to
node_modules/import_nameandnode_modules/@types/import_nameis not something I would like to see.Also, please, please, please improve documentation on "ambient modules". I've read the section seven times now, I still have no idea what the ambient modules are, how to define them and where to put the specs so that they are picked up by TS. Espec
It would be awesome, if there was a small section "you want to import module X. you create a file X.d.ts here. Then you do this and that and this"
Reacted by Fabian Eichenberger, nino-porcino, Tony Davis, Sindre Sorhus, Andrew Chen, Jakub Beránek, Tom Piarulli, Nathan Johnson, Christopher Hiller, Jessica Franco and 14 moreI followed a chain of four closed tickets to get here. Glad to see the issue was addressed. Could someone please point to docs for this feature? How do I use it? For my sake, and for everyone else who may end up here. :)
This is part of
typescript@2.1.3release, so for now you will neednpm install typescript@next.Now having an import like
import foo from "Foo"the compiler will check if there is a packageFoo, e.g.node_modules\Foo\index.jsif one is available, even if it does not have a .d.ts file along with it, no error will be reported. the type of the imports will beany.if you use
--noImplicitAny, you would get these import flagged as implicit anys.hope that helps.
That helps a lot, thank you. It seems like for now (v2.0.10) we can also use
declare module "Foo";?yes. that is Shorthand ambient module declarations
Now having an import like import foo from "Foo" the compiler will check if there is a package Foo, e.g. node_modules\Foo\index.js if one is available, even if it does not have a .d.ts file along with it, no error will be reported. the type of the imports will be any.
Does this mean that if you've got a node module that doesn't use
index.jsbut instead relies on amainfield inpackage.jsonthat this feature doesn't work?Now having an import like import foo from "Foo" the compiler will check if there is a package Foo, e.g. node_modules\Foo\index.js if one is available, even if it does not have a .d.ts file along with it, no error will be reported. the type of the imports will be any.
And what about relatively referenced JS modules?
import Blah from './blah.js';In this case, Blah ends up as "type Blah" and TS tries its best to infer the shape of the exported object from blah.js, which in my case, was wrong (it only identified some of the properties on the object - others get errors of property key does not exist on value of type Blah). Hence, Blah is NOT of type any! I have to do (Blah as any).method() to get it to work.
I would think many would be hitting this issue mixing TS and JS. We're using an ejected create-react-app with TS support added to the webpack config via ts-loader. I expected it to just work without fuss, sadly not the case.
Longer explanation with code sample: http://stackoverflow.com/questions/43954320/es6-import-of-relative-path-js-module-type-not-fully-inferred-how-to-declare
Does quick fix 1 only work if blah.d.ts is in the same location as blah.js? It does work, but my team may not want .d.ts files polluting their code directories (we're slowly using Typescript on new areas of the system, 95% of it is an ES6 codebase).
Does quick fix 1 only work if blah.d.ts is in the same location as blah.js?
If you import the module with its name (i.e.
import d from "foo";) and not with a relative path (i.e.import d from "./foo";) then you can either 1. put the .d.ts next to the .js, 2. put it somewhere else, and add a path mapping, or 3. add it to a folder, e.g../types/foo/index.d.tsand add./typesto yourtypeRootsin thetsconfig.json.if it is a relative import, then you need to put the .d.ts next to the .js
So in instances where one imports relatively (this would be especially common in a create-react-app codebase), it seems these are the options;
- Hope the TS compiler can infer your JS right
- If it doesn't, you have these options:
- (blah as any).method() on every use of the import
- add a new variable to your .ts such as const blahAny: any = blah;
- add a .d.ts to the same location as the .js, which may not be desirable or appreciated by the owners of that location.
I wish we could opt-in to having the same behavior as modules within node_modules, wherein if a typing is not found, the module could default to type any. I saw someone suggest
import blah: any from './blah.js',which would be clean and simple syntax specifying the programmer's intent.- locked and limited conversation to collaborators
on Jun 19, 2018
Consider importing an untyped module, eg. exceljs:
This results in an error that the module exceljs is not found. There is at least two ways to fix this:
allowJs: trueandmaxNodeModulesJsDepth: 1I think it would be better if instead we update module resolution semantics such that when we find an appropriate package.json without a typings entry, we store it away. Then if module resolution fails (ie. we also can't find an @types/exceljs), we go back and import the untyped package.json as a JS import. Thoughts?
You might argue that this should only be allowed with --allowJs, but it might also make sense to just always use this behavior when using node resolution rules as you may still not want to allow JS in your own project while still allowing your dependencies to be authored in JS without typings.