Implement a node script wrapper for our tests so that we can output a…

… hint when failing (#4745)

bin/output-fixing-commands.js

@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+// @flow
+
+// This file runs before linting commands and intercept errors so that more
+// friendly errors can be output.
+
+const cp = require('child_process');
+
+const fixingCommands = {
+  lint: 'lint-fix',
+  'lint-js': 'lint-fix-js',
+  'lint-css': 'lint-fix-css',
+  'prettier-run': 'prettier-fix',
+  test: 'test -u',
+};
+
+const command = process.argv.slice(2);
+
+const result = cp.spawnSync(command[0], command.slice(1), { stdio: 'inherit' });
+
+if (result.status !== 0) {
+  process.exitCode = result.status;
+  const currentScriptName = process.env.npm_lifecycle_event;
+  if (currentScriptName && currentScriptName in fixingCommands) {
+    console.log(
+      '💡 You might be able to fix the error by running `yarn ' +
+        fixingCommands[currentScriptName] +
+        '`'
+    );
+  }
+}

package.json

@@ -13,13 +13,13 @@
     "build-l10n-prod:quiet": "yarn build:clean && yarn build-photon && cross-env NODE_ENV=production L10N=1 webpack",
     "build-l10n-prod": "yarn build-l10n-prod:quiet --progress",
     "build-photon": "webpack --config res/photon/webpack.config.js",
-    "lint": "run-p lint-js lint-css prettier-run",
+    "lint": "node bin/output-fixing-commands.js run-p lint-js lint-css prettier-run",
     "lint-fix": "run-p lint-fix-js lint-fix-css prettier-fix",
-    "lint-js": "eslint *.js bin src --report-unused-disable-directives --cache --cache-strategy content",
+    "lint-js": "node bin/output-fixing-commands.js eslint *.js bin src --report-unused-disable-directives --cache --cache-strategy content",
     "lint-fix-js": "yarn lint-js --fix",
-    "lint-css": "stylelint \"src/**/*.css\" \"res/**/*.css\"",
+    "lint-css": "node bin/output-fixing-commands.js stylelint \"src/**/*.css\" \"res/**/*.css\"",
     "lint-fix-css": "yarn lint-css --fix",
-    "prettier-run": "prettier --check . --cache --cache-strategy content --cache-location .prettiercache",
+    "prettier-run": "node bin/output-fixing-commands.js prettier --check . --cache --cache-strategy content --cache-location .prettiercache",
     "prettier-fix": "prettier --write . --cache --cache-strategy content --cache-location .prettiercache",
     "flow": "flow --max-warnings 0",
     "flow:ci": "flow check --max-warnings 0",
@@ -37,7 +37,7 @@
     "start-examples": "ws -d examples/ -s index.html -p 4242",
     "start-docs": "ws -d docs-user/ -p 3000",
     "start-photon": "node res/photon/server",
-    "test": "cross-env LC_ALL=C TZ=UTC NODE_ENV=test jest",
+    "test": "node bin/output-fixing-commands.js cross-env LC_ALL=C TZ=UTC NODE_ENV=test jest",
     "test-all": "run-p --max-parallel 4 flow license-check lint test test-alex test-lockfile",
     "test-all:ci": "run-p --max-parallel 4 flow:ci license-check lint test test-alex test-lockfile",
     "test-build-coverage": "jest --coverage --coverageReporters=html",