Add --cache to eslint invocations for speed

.gitignore

@@ -1,6 +1,7 @@
 node_modules
 npm-debug.log
 .DS_Store
+.eslintcache
 *.sw[po]
 *.xpi
 *.pyc

.mcignore

@@ -5,6 +5,7 @@ npm-debug.log
 *.pyc
 *.update.rdf
 .gitignore
+.eslintcache
 
 /.git/
 /data/locales.json

package.json

@@ -135,8 +135,8 @@
     "tddmc": "karma start karma.mc.config.js --tdd",
     "debugcoverage": "open logs/coverage/index.html",
     "lint": "npm-run-all lint:*",
-    "lint:eslint-check": "eslint --print-config . | eslint-config-prettier-check",
-    "lint:eslint": "eslint --ext=.js,.jsm,.jsx .",
+    "lint:eslint-check": "eslint --cache --print-config . | eslint-config-prettier-check",
+    "lint:eslint": "eslint --cache --ext=.js,.jsm,.jsx .",
     "lint:sasslint": "sass-lint -v -q",
     "strings-import": "node ./bin/strings-import.js",
     "test": "npm run testmc",

yamscripts.yml

@@ -67,8 +67,8 @@ scripts:
 
 # lint: Run eslint and sass-lint
   lint:
-    eslint-check: eslint --print-config . | eslint-config-prettier-check
-    eslint: eslint --ext=.js,.jsm,.jsx .
+    eslint-check: eslint --cache --print-config . | eslint-config-prettier-check
+    eslint: eslint --cache --ext=.js,.jsm,.jsx .
     sasslint: sass-lint -v -q
 
 # strings-import: Replace local strings with those from l10n-central