I have an ASP.NET Core website with TypeScript. My ASP.NET Core setup is typical in that it has a node_modules folder in the root of the project and then I copy the source folders of the libraries I'm using from node_modules to wwwroot/lib using Gulp.
Therefore, I have date-fns source files in wwwroot/lib/date-fns and in my TypeScript .ts file I'm trying to import it like this:
import * as fns from "lib/date-fns/i.am.stuck.here.js";
The VS2019 code editor is autocompleting the folder so it can see it, but I don't know what .js file to enter, it doesn't suggest one.
I also don't know if I should import * or something else. I'm not a frontend dev so I struggle with TS and JS and imports and requires and all that stuff.
I can see that date-fns has a typings file so I assume this is straight forward for those in the know.
Update:
I found this:
https://github.com/date-fns/date-fns/blob/master/examples/typescript/example.ts
Which is strange because updating my code to the below, which is auto-suggested as the editor reads the folders on disk:
import { format } from "lib/date-fns";
Leaves me with an error:
error TS2307: Cannot find module 'lib/date-fns' or its corresponding type declarations.
When I was importing moment.js I pointed it at the .js file itself, which was auto-suggested.
Also, if I change to 'lib/date-not-exist' I get the same error, so I'm unable to tell if it's a file path existence issue or a TypeScript locating module issue.
Update:
I can get TypeScript to squelch the error and presumably find a module with this:
import * as dformat from "lib/date-fns/format/index";
But this doesn't work because:
var result = dformat(date, 'dd.MM.yyy HH:mm:ss');
Gives error:
error TS2349: This expression is not callable.
See my answer in Import a JavaScript module or library into TypeScript if you're having problems importing modules generally using TypeScript and JavaScript in the browser.