Use eslint cache (#12668)

.gitignore

@@ -13,6 +13,7 @@
 /db/*.sqlite3-journal
 
 # Ignore all logfiles and tempfiles.
+.eslintcache
 /log/*
 !/log/.keep
 /tmp
@@ -61,4 +62,3 @@ ubuntu-xenial-16.04-cloudimg-console.log
 
 # Ignore Docker option files
 docker-compose.override.yml
-

package.json

@@ -12,7 +12,7 @@
     "start": "node ./streaming/index.js",
     "test": "${npm_execpath} run test:lint:js && ${npm_execpath} run test:jest",
     "test:lint": "${npm_execpath} run test:lint:js && ${npm_execpath} run test:lint:sass",
-    "test:lint:js": "eslint --ext=js .",
+    "test:lint:js": "eslint --ext=js . --cache",
     "test:lint:sass": "sass-lint -v",
     "test:jest": "cross-env NODE_ENV=test jest --coverage"
   },