Migrate from prettier to eslint to match firebase/firebase-tools styling (#1194)

Let's bite the bullet - match styling of firebase/firebase-tools and start using eslint over prettier.

This change effectively touches almost all files in this repo, especially since eslint prefers double-quotes over single-quotes.

I've made couple of other changes to make eslint errors go away. Things like:

1) Eliminate dangling promises
2) Remove empty function definition (prefer `()=>undefined` over `()=>{}`)
3) Remove unused arguments from function definitions

In theory, these are just linter changes without changes to the runtime behavior. v4 launches will need good tests and bugbash anyway, so this feels like a great time to commit to this migration.

Author: taeold

.eslintignore

@@ -0,0 +1,11 @@
+coverage
+dev
+lib
+node_modules
+docgen
+v1
+v2
+logger
+dist
+spec/fixtures
+scripts/**/*.js

.eslintrc.js

@@ -0,0 +1,77 @@
+module.exports = {
+  env: {
+    es6: true,
+    node: true,
+  },
+  extends: [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:@typescript-eslint/recommended-requiring-type-checking",
+    "plugin:jsdoc/recommended",
+    "google",
+    "prettier",
+  ],
+  rules: {
+    "jsdoc/newline-after-description": "off",
+    "jsdoc/require-jsdoc": ["warn", { publicOnly: true }],
+    "no-restricted-globals": ["error", "name", "length"],
+    "prefer-arrow-callback": "error",
+    "prettier/prettier": "error",
+    "require-atomic-updates": "off", // This rule is so noisy and isn't useful: https://github.com/eslint/eslint/issues/11899
+    "require-jsdoc": "off", // This rule is deprecated and superseded by jsdoc/require-jsdoc.
+    "valid-jsdoc": "off", // This is deprecated but included in recommended configs.
+
+    "no-prototype-builtins": "warn",
+    "no-useless-escape": "warn",
+    "prefer-promise-reject-errors": "warn",
+  },
+  overrides: [
+    {
+      files: ["*.ts"],
+      rules: {
+        "jsdoc/require-param-type": "off",
+        "jsdoc/require-returns-type": "off",
+
+        // Google style guide allows us to omit trivial parameters and returns
+        "jsdoc/require-param": "off",
+        "jsdoc/require-returns": "off",
+
+        "@typescript-eslint/no-invalid-this": "error",
+        "@typescript-eslint/no-unused-vars": "error", // Unused vars should not exist.
+        "@typescript-eslint/no-misused-promises": "warn", // rule does not work with async handlers for express.
+        "no-invalid-this": "off", // Turned off in favor of @typescript-eslint/no-invalid-this.
+        "no-unused-vars": "off", // Off in favor of @typescript-eslint/no-unused-vars.
+        eqeqeq: ["error", "always", { null: "ignore" }],
+        camelcase: ["error", { properties: "never" }], // snake_case allowed in properties iif to satisfy an external contract / style
+
+        // Ideally, all these warning should be error - let's fix them in  the future.
+        "@typescript-eslint/no-unsafe-argument": "warn",
+        "@typescript-eslint/no-unsafe-assignment": "warn",
+        "@typescript-eslint/no-unsafe-call": "warn",
+        "@typescript-eslint/no-unsafe-member-access": "warn",
+        "@typescript-eslint/no-unsafe-return": "warn",
+        "@typescript-eslint/restrict-template-expressions": "warn",
+      },
+    },
+    {
+      files: ["*.spec.*"],
+      env: {
+        mocha: true,
+      },
+      rules: {},
+    },
+  ],
+  globals: {},
+  parserOptions: {
+    project: "tsconfig.json",
+  },
+  plugins: ["prettier", "@typescript-eslint", "jsdoc"],
+  settings: {
+    jsdoc: {
+      tagNamePreference: {
+        returns: "return",
+      },
+    },
+  },
+  parser: "@typescript-eslint/parser",
+};

.github/ISSUE_TEMPLATE/---report-a-bug.md

@@ -1,9 +1,9 @@
 ---
-name: '⚠️ Report a Bug'
+name: "⚠️ Report a Bug"
 about: Think you found a bug in the firebase-functions SDK? Report it here. Please do not use this form if your function is deployed successfully but not working as you expected.
-title: ''
-labels: ''
-assignees: ''
+title: ""
+labels: ""
+assignees: ""
 ---
 
 <!-- DO NOT DELETE

.github/workflows/postmerge.yaml

@@ -16,7 +16,7 @@ name: Post-merge tests
 on:
   workflow_dispatch:
   workflow_run:
-    workflows: ['CI Tests']
+    workflows: ["CI Tests"]
     types: [completed]
     branches: [master]
 
@@ -38,16 +38,16 @@ jobs:
 
       - uses: google-github-actions/auth@v0
         with:
-          credentials_json: '${{ secrets.CF3_INTEGRATION_TEST_GOOGLE_CREDENTIALS }}'
+          credentials_json: "${{ secrets.CF3_INTEGRATION_TEST_GOOGLE_CREDENTIALS }}"
           create_credentials_file: true
 
-      - name: 'Set up Cloud SDK'
+      - name: "Set up Cloud SDK"
         uses: google-github-actions/setup-gcloud@v0
 
-      - name: 'Setup Firebase CLI'
+      - name: "Setup Firebase CLI"
         run: npm i -g firebase-tools
 
-      - name: 'Run integration test'
+      - name: "Run integration test"
         run: npm run test:postmerge
 
       - name: Print debug logs

.github/workflows/test.yaml

@@ -8,6 +8,23 @@ env:
   CI: true
 
 jobs:
+  lint:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request'
+    strategy:
+      matrix:
+        node-version:
+          - "16"
+    steps:
+      - uses: actions/checkout@v3
+        with:
+          fetch-depth: 0
+      - uses: actions/setup-node@v3
+        with:
+          node-version: ${{ matrix.node-version }}
+          cache: npm
+      - run: npm ci
+      - run: npm run lint
   unit:
     runs-on: ubuntu-latest
     strategy:
@@ -20,18 +37,15 @@ jobs:
       - uses: actions/setup-node@v1
         with:
           node-version: ${{ matrix.node-version }}
-
       - name: Cache npm
         uses: actions/cache@v1
         with:
           path: ~/.npm
           key: ${{ runner.os }}-node-${{ matrix.node-version }}-${{ hashFiles('**/package-lock.json') }}
-
       - run: npm ci
-      - run: npm run lint
-      - run: npm run format
       - run: npm run test
   integration:
+    needs: "unit"
     runs-on: ubuntu-latest
     strategy:
       matrix:
@@ -43,12 +57,10 @@ jobs:
       - uses: actions/setup-node@v1
         with:
           node-version: ${{ matrix.node-version }}
-
       - name: Cache npm
         uses: actions/cache@v1
         with:
           path: ~/.npm
           key: ${{ runner.os }}-node-${{ matrix.node-version }}-${{ hashFiles('**/package-lock.json') }}
-
-      - run: npm install
+      - run: npm ci
       - run: npm run test:bin

.mocharc.yaml

@@ -4,5 +4,5 @@ extension:
 package: ./package.json
 reporter: spec
 require:
-  - 'ts-node/register'
-  - 'source-map-support/register'
+  - "ts-node/register"
+  - "source-map-support/register"

.prettierignore

@@ -1,3 +1,4 @@
-lib
-package.json
-spec/fixtures/credential/unparsable.key.json
+/node_modules
+/lib/**/*
+/CONTRIBUTING.md
+/docgen

.prettierrc

@@ -0,0 +1,3 @@
+module.exports = {
+  printWidth: 100,
+};

.prettierrc.js

@@ -23,15 +23,13 @@ _Please avoid double posting across multiple channels!_
 
 ```js
 // functions/index.js
-const functions = require('firebase-functions');
-const notifyUsers = require('./notify-users');
-
-exports.newPost = functions.database
-  .ref('/posts/{postId}')
-  .onCreate((snapshot, context) => {
-    functions.logger.info('Received new post with ID:', context.params.postId);
-    return notifyUsers(snapshot.val());
-  });
+const functions = require("firebase-functions");
+const notifyUsers = require("./notify-users");
+
+exports.newPost = functions.database.ref("/posts/{postId}").onCreate((snapshot, context) => {
+  functions.logger.info("Received new post with ID:", context.params.postId);
+  return notifyUsers(snapshot.val());
+});
 ```
 
 ## Contributing