Experimental-[Typescript] Use default import instead of namespaced import

[hmt]

In this PR I changed the namespaced import of url-parse to default import. The namespaced import caused all kinds of trouble with my rollup configuration and it seems to work either way. I might be wrong but to my knowledge TS doesn't need namespaced imports anymore. Let me know if this is totally off and should be solved differently.

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  Thank you for looking into this: @TiFu (2017/07) @taxpon (2017/07) @sebastianhaas (2017/07) @kenisteward (2017/07) @Vrolijkx (2017/09) @macjohnny (2018/01) @topce (2018/10) @akehir (2019/07) @petejohansonxo (2019/11) @amakhrov (2020/02)

[TiFu]

Thank you for the PR! Looks like there is some issue with the way the default import works versus what we had before - see the CI output below. Is it possible that we would have to call a function of URLParse or remove the new keyword?

 1) PetApi
       addPet:
     TypeError: url_parse_1.default is not a constructor
      at new RequestContext (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/http/http.ts:60:20)
      at ServerConfiguration.makeRequestContext (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/servers.ts:47:10)
      at PetApiRequestFactory.<anonymous> (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/apis/PetApi.ts:35:47)
      at step (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/dist/apis/PetApi.js:46:23)
      at Object.next (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/dist/apis/PetApi.js:27:53)
      at /home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/dist/apis/PetApi.js:21:71
      at new Promise (<anonymous>)
      at __awaiter (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/dist/apis/PetApi.js:17:12)
      at PetApiRequestFactory.addPet (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/dist/apis/PetApi.js:65:16)
      at ObservablePetApi.addPet (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/types/ObservableAPI.ts:35:56)
      at PromisePetApi.addPet (/home/travis/build/OpenAPITools/openapi-generator/samples/openapi3/client/petstore/typescript/builds/default/types/PromiseAPI.ts:31:30)
      at Context.<anonymous> (test/api/PetApi.test.ts:23:16)
      at processImmediate (internal/timers.js:461:21)

[hmt]

I'm not entirely sure what is going on but I'm using es6 in my tsconfig via the es6 flag unlike the tests that use es5 and commonjs. Should there be another build for es6 only?

[TiFu]

We could do a separate build for es6 - either way the code would have to work for both es5 and es6.

Could you elaborate a bit more on what trouble you ran into with the namespaced import?

[hmt]

I'm using vite for an app. As I understand it it uses different build systems for development and production. In dev mode it works fine but in production mode it switches to rollup.

So when I use rollup to build the code I end up with this error message:

Uncaught (in promise) TypeError: URLParse is not a constructor
    RequestContext http.js:35
    makeRequestContext servers.js:22
    getSchuelerListe SchuelerApi.js:60
    1 SchuelerApi.js:7
    1 SchuelerApi.js:3
    getSchuelerListe SchuelerApi.js:53
    getSchuelerListe ObservableAPI.js:1854
    getSchuelerListe ObjectParamAPI.js:424
    <anonymous> main.js:6
http.js:35:19

[TiFu]

Mhh, to me that sounds like an issue with rollout - or an incompatibility between ES5 and 6.

My way forward would either be raising this with rollout and getting their opinion on this issue - or looking at what the difference in generated code is between dev and prod. That should at least give a hint of what's wrong and from there may be why it is happening.

[wing328]

We could do a separate build for es6 - either way the code would have to work for both es5 and es6.

Shall we consider dropping es5 support in the TS generators?

We've already done it in the javascript generator as part of the 5.0.0 release.