feat: make the lib isomorphic

[alanpoulain]

Fixes #275.

In order to make this lib isomorphic (usable both in the browser and in Node.js), these changes have been made:

• do not use process global variable directly
• use fetch instead of http (Fetch API is available in Node.js as experimental and if not, can be polyfilled easily).
• do not use url (use URL API instead).

[philsturgeon]

Thank you so much @alanpoulain!

Linter has noticed a few things:

/home/runner/work/json-schema-ref-parser/json-schema-ref-parser/lib/resolvers/http.js
Error:     3:7   error  'http' is assigned a value but never used   no-unused-vars
Error:     4:7   error  'https' is assigned a value but never used  no-unused-vars
Error:   148:13  error  Strings must use doublequote                quotes
Error:   150:48  error  Strings must use doublequote                quotes
Error:   150:60  error  Strings must use doublequote                quotes

/home/runner/work/json-schema-ref-parser/json-schema-ref-parser/lib/util/url.js
Warning:   25:18  warning  'url' is already declared in the upper scope  no-shadow

I would just fix those myself but that last one might need a closer eye to make sure there's nothing funny going on.

[philsturgeon]

I had a go at fixing the linting issues myself in #282 but there is a test failure too.

  148 passing (525ms)
  1 failing

  1) HTTP options
       http.headers
         should override default HTTP headers:
     ResolverError: Error reading file "https://httpbin.org/headers"
      at onError (lib/parse.js:32:232)

Can you make sure npm run test:node is working before you push?

Thank you!

[alanpoulain]

Sorry I forgot to run the linter, it should not be an issue anymore!

For the test failure, I was testing with Node.js 18, hence I didn't have the failure.
It should be fixed now: I added the node-fetch polyfill in the tests.
I've also added node-abort-controller for Node.js 14 tests.

I have updated the CI as well.

I've also added a mention to use a polyfill in the README.

[philsturgeon]

Thank you for such a speedy fix!

There's one more issue popping up on Node v14 and I have seen it in a few places, not sure why...

Run npm run coverage:node

> @apidevtools/json-schema-ref-parser@0.0.0-dev coverage:node D:\a\json-schema-ref-parser\json-schema-ref-parser
> nyc node_modules/mocha/bin/mocha



  File names with special characters
    1) should parse successfully


  0 passing (47ms)
  1 failing

  1) File names with special characters
       should parse successfully:
     TypeError [ERR_INVALID_URL]: Invalid URL: specs/__(%7B%5B%20%25%20&%20$%20%23%20@%20%60%20~%20,)%7D%5D__/__(%7B%5B%20%25%20&%20$%20%23%20@%20%60%20~%20,)%7D%5D__.yaml
      at new NodeError (internal/errors.js:322:7)
      at onParseError (internal/url.js:270:9)
      at new URL (internal/url.js:346:5)
      at Object.resolve (lib\util\url.js:8:137)
      at $RefParser.parse (lib\index.js:46:39)
      at Context.<anonymous> (test\specs\__({[ % & $ # @ ` ~ ,)}]__\special-characters.spec.js:13:33)
      at processImmediate (internal/timers.js:464:21)

Any chance you can smash that one too?

[alanpoulain]

That's weird, I cannot reproduce it on my machine, it seems a Windows only issue.
It doesn't seem related to the changes of this PR too.
I won't have time to look at it before a few days.

[philsturgeon]

@alanpoulain thank you, I'll make a fresh issue for it. Merged!

[lucy-loo]

@philsturgeon can you publish a new version? 🙏