Fixes #2398 If the user has a particularly large node_modules folder and uses globs for `parserOption.project`, then the `glob` library can spend a decent chunk of time searching the `node_modules` folder. In some cases, this can be on the order of hundreds to thousands of milliseconds. This wouldn't be a problem, but for safety and correctness during a persistent parse, we have to do this check for every call to the parser (i.e. every file that's being linted). Over a whole project, this can easily add up to many, many seconds wasted. Previously, we: - applied the project globs, one by one - then manually excluded `tsconfig`s from the list. This meant that we are always slow. I remember I did this because I had issues getting `glob`'s `ignore` option to work at all. ## The solution `globby` is a better glob library: - it accepts an array of globs, which saves us doing manual looping - it supports exclusion globs (globs prefixed with `!`), which are evaluated as part of the glob process - it has caching built in by default This allows us to evaluate all of the `project` globs at once, as opposed to one at a time (so should be less duplicated work). This also allows us to evaluate the `projectFolderIgnoreList` at the same time as the `project` globs (so should be no useless work done). All of these together should cut the glob evaluation time down to ~50ms for the first parse, and ~2ms for each parse after that (due to caching). For comparison, previously, in bad cases we would spend ~3-500ms, per project, per parsed file. Example to illustrate how much faster this can potentially be: For a project that provides 2 globs and has 100 files. Before: 300ms * 2 * 100 = 60,000ms (60s) After: 50ms + 2 * 100 = 250ms This should also save a non-trival amount of time in other, more optimal setups. BREAKING CHANGE: - removes the ability to supply a `RegExp` to `projectFolderIgnoreList`, and changes the meaning of the string value from a regex to a glob.

Commits

Commits on Aug 24, 2020

feat(typescript-estree): switch to globby