fix: Improve parse perf when using @typescript-eslint/parser

[bradzacher]

Fixes #1408
See the above issue for justification.

[coveralls]

Coverage remained the same at 97.896% when pulling 32704da on bradzacher:patch-1 into 3b21de6 on benmosher:master.

[ljharb]

This looks good, but rather than mutating the new parserOptions object, maybe we could change this entire block to:

parserOptions = Object.assign({}, parserOptions, {
  ecmaFeatures: Object.assign({}, parserOptions.ecmaFeatures),
  comment: true,
  attachComment: true,
  tokens: true,
  loc: true,
  range: true,
  filePath: path,
  project: undefined,
  projects: undefined,
})

?

[ljharb]

LGTM; i'm not sure if appveyor is failing on master or only on this PR.

[bradzacher]

@ljharb - appveyor was passing with my first commit - it appears using Object.assign breaks some tests.
It's a bit hard to investigate, because locally no matter what I do, there are many failing tests locally for some reason...
I'll just revert the commit.

[ljharb]

That's a shame. We can fix that in a followup PR.

[benmosher]

No need to re-Object.assign, the object is already shallowly cloned on line 19. LGTM! thanks!

[lencioni]

Thanks for working on this! Excited to see this land.

[ljharb]

@benmosher it’s still better to create a new object all at once instead of mutating it at any point.

[benmosher]

fair enough, but even if we used destructuring to remove the fields (iff this file was being transpiled) the Babel'd version would start with an empty object and add fields.

given that we can't predict all the fields we need to pass through, this seems acceptable to me. I'm good to merge if you are, @ljharb.

[ljharb]

Definitely, we can look into creating the object differently in a follow up. Once tests are passing, it’s good to go.

[bradzacher]

Once tests are passing, it’s good to go.

@ljharb - having a look, the travis CI tests that are failing are the same ones that are failing in master right now (tests against eslint v2/v3)

[ljharb]

We should fix those in master first, then, and rebase this PR

[deser]

If tests are failing in master can we just merge this and release?

[ljharb]

No, we shouldn’t merge and must not release without passing tests.

[deser]

ok. sorry

[benmosher]

sorry @deser, test failures were on me but they are fixed now 👍🏼

[bradzacher]

AppVeyor failed during install time on node8.
It looks like a transient error, but I don't have permission to retry the build.
Could someone with permissions please retry that build?

[00:00:33] npm ERR! code Z_BUF_ERROR
[00:00:33] npm ERR! errno -5
[00:00:33] npm ERR! zlib: unexpected end of file

If not I can just push a fluff commit to make it retry

[hayes]

thanks for getting this merged!

@ljharb can you cut a release of eslint-module-utils as well? it looks like only eslint-plugin-import got released after this change

[ljharb]

Oops, yes will do today.

[ljharb]

v2.4.1 of eslint-module-utils is published.