Support definitions that don't have tags. Closes #140

[brendo]

Note I've pulled in an example from the OAI project which requires more tickets before we can actually display it in full. For now, it's just used as an example of a definition without tags.

Notes:

• sortFunc only applies to definitions with tags. It just doesn't make much sense otherwise.
• minor bumps to eslint packages (no more warnings when installing)
• start to extract logic out of the one parser by creating a navigationParser file. It's a start, but honestly I'm not super worried about optimising too much in this space until we pull this out as a separate package.

Example:

http://localhost:8200/?url=https://raw.githubusercontent.com/OAI/OpenAPI-Specification/OpenAPI.next/examples/v3.0/api-with-examples.yaml

[nfour]

I just want to add, it would be nice to integrate benchmarks in our tests, for regressions in the parser (or not-regressions!).

Below is an example benchmark test:

export function benchmark (timeout, fn) {
  const timeoutAt = Date.now() + timeout
  let iterations = 0

  do {
    fn()
    ++iterations
  } while (Date.now() <= timeoutAt)

  return iterations
}

it('benchmark', () => {
  const base = 2000 // Keep updating this manually, but for CI?
  // In future you'd want to import the previous stable version as a dev dep (maybe git commit hash?) and test against that

  const current = benchmark(500, () => {
    doSomeParsing('foo')
  })

  const percentDiff = Math.round(((current - base) / base) * 100)

  console.dir(`doSomeParsing: ${base} -> ${current} (%${percentDiff})`)

  expect(percentDiff).toBeGreaterThan(20) // It must be 20 percent faster
}

In theory iterations will scale across systems, but the baseline will be awkward.

[brendo]

Good idea, we should track this as a separate ticket. I raised #146

[nfour]

👌