Enable ESLint caching (#645)

Closes #550.

.changeset/loud-apricots-leave.md

@@ -0,0 +1,7 @@
+---
+"skuba": minor
+---
+
+format, lint: Enable ESLint caching
+
+ESLint now writes to a local `.eslintcache` store. This speeds up subsequent runs of `skuba format` and `skuba lint` as they can skip unchanged files.

.gitignore

@@ -10,6 +10,7 @@ node_modules*/
 /tmp*/
 
 .DS_Store
+.eslintcache
 .npmrc
 *.tgz
 *.tsbuildinfo

src/cli/__snapshots__/format.int.test.ts.snap

@@ -62,8 +62,10 @@ Prettier
 Initialising Prettier...
 Detected project root: <random>
 Discovering files...
-Discovered 6 files.
+Discovered 7 files.
 Formatting files...
+.eslintcache
+  parser: -
 b.md
   parser: markdown
 c.json

src/cli/__snapshots__/lint.int.test.ts.snap

@@ -64,8 +64,10 @@ ESLint   │ ○ d.js
 Prettier │ Initialising Prettier...
 Prettier │ Detected project root: <random>
 Prettier │ Discovering files...
-Prettier │ Discovered 6 files.
+Prettier │ Discovered 7 files.
 Prettier │ Linting files...
+Prettier │ .eslintcache
+Prettier │   parser: -
 Prettier │ b.md
 Prettier │   parser: markdown
 Prettier │ c.json

src/cli/adapter/eslint.ts

@@ -32,9 +32,7 @@ export const runESLint = async (
   logger.debug('Initialising ESLint...');
 
   const engine = new ESLint({
-    // TODO: enable this once we have a less overzealous `skuba configure` that
-    // everyone can apply to update their `.gitignore` files.
-    // cache: true,
+    cache: true,
     extensions: ['js', 'ts', 'tsx'],
     fix: mode === 'format',
     reportUnusedDisableDirectives: 'error',

src/cli/configure/analysis/__snapshots__/project.test.ts.snap

@@ -68,6 +68,7 @@ node_modules*/
 /tmp*/
 
 .DS_Store
+.eslintcache
 .npmrc
 *.tgz
 *.tsbuildinfo

template/base/_.gitignore

@@ -12,6 +12,7 @@ node_modules*/
 /tmp*/
 
 .DS_Store
+.eslintcache
 .npmrc
 *.tgz
 *.tsbuildinfo