From 2529ee6508335ca864dde1d1b741a65b462671cb Mon Sep 17 00:00:00 2001
From: Jack Franklin <jacktfranklin@chromium.org>
Date: Tue, 14 Apr 2020 12:08:52 +0100
Subject: [PATCH] chore(eslint): add eslint typescript linting (#5635)

This commit adds linting for `*.ts` files and loads up the recommended
list of TS rules from the ESLint TypeScript plugin. We can adjust the
exact rules overtime, but starting with the recommended list seems
sensible.
---
 .eslintignore            |  6 ++++++
 .eslintrc.js             | 34 ++++++++++++++--------------------
 package.json             |  4 +++-
 src/DeviceDescriptors.ts |  6 +++---
 4 files changed, 26 insertions(+), 24 deletions(-)

diff --git a/.eslintignore b/.eslintignore
index 6e6149f2c22fc..54c6043ef961a 100644
--- a/.eslintignore
+++ b/.eslintignore
@@ -6,3 +6,9 @@ node6/*
 node6-test/*
 experimental/
 lib/
+src/externs.d.ts
+src/protocol.d.ts
+/index.d.ts
+# We ignore this file because it uses ES imports which we don't yet use
+# in the Puppeteer src, so it trips up the ESLint-TypeScript parser.
+utils/doclint/generate_types/test/test.ts
diff --git a/.eslintrc.js b/.eslintrc.js
index 49c970c4b6b7f..a0bf98660eb0e 100644
--- a/.eslintrc.js
+++ b/.eslintrc.js
@@ -1,34 +1,18 @@
 module.exports = {
     "root": true,
-
     "env": {
         "node": true,
         "es6": true
     },
 
-    "parserOptions": {
-        "ecmaVersion": 9
-    },
+    "parser": "@typescript-eslint/parser",
 
     "plugins": [
-        "mocha"
+        "mocha",
+        "@typescript-eslint"
     ],
 
-    /**
-     * ESLint rules
-     *
-     * All available rules: http://eslint.org/docs/rules/
-     *
-     * Rules take the following form:
-     *   "rule-name", [severity, { opts }]
-     * Severity: 2 == error, 1 == warning, 0 == off.
-     */
     "rules": {
-        /**
-         * Enforced rules
-         */
-
-
         // syntax preferences
         "quotes": [2, "single", {
             "avoidEscape": true,
@@ -115,5 +99,15 @@ module.exports = {
 
         // ensure we don't have any it.only or describe.only in prod
         "mocha/no-exclusive-tests": "error"
-    }
+    },
+    "overrides": [
+        {
+            // apply TypeScript linting to the TS files in src/
+            "files": ["src/*.ts"],
+            "extends": [
+                'plugin:@typescript-eslint/eslint-recommended',
+                'plugin:@typescript-eslint/recommended',
+            ]
+        }
+    ]
 };
diff --git a/package.json b/package.json
index 7048a6156a464..aaf363351b24d 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
     "prepublishOnly": "npm run tsc",
     "dev-install": "npm run tsc && node install.js",
     "install": "node install.js",
-    "lint": "([ \"$CI\" = true ] && eslint --quiet -f codeframe . || eslint .) && npm run tsc && npm run doc",
+    "lint": "([ \"$CI\" = true ] && eslint --ext js --ext ts --quiet -f codeframe . || eslint --ext js --ext ts .) && npm run tsc && npm run doc",
     "doc": "node utils/doclint/cli.js",
     "tsc": "tsc --version && tsc -p . && cp src/protocol.d.ts lib/ && cp src/externs.d.ts lib/",
     "apply-next-version": "node utils/apply_next_version.js",
@@ -53,6 +53,8 @@
     "@types/rimraf": "^2.0.2",
     "@types/tar-fs": "^1.16.2",
     "@types/ws": "^6.0.1",
+    "@typescript-eslint/eslint-plugin": "^2.28.0",
+    "@typescript-eslint/parser": "^2.28.0",
     "commonmark": "^0.28.1",
     "cross-env": "^5.0.5",
     "eslint": "^6.8.0",
diff --git a/src/DeviceDescriptors.ts b/src/DeviceDescriptors.ts
index 945e5cadf7f47..2db6452de57e3 100644
--- a/src/DeviceDescriptors.ts
+++ b/src/DeviceDescriptors.ts
@@ -25,7 +25,7 @@ interface Device {
     hasTouch: boolean;
     isLandscape: boolean;
   };
-};
+}
 
 const devices: Device[] = [
   {
@@ -888,8 +888,8 @@ type DevicesMap = {
 
 const devicesMap: DevicesMap = {};
 
-for (const device of devices) {
+for (const device of devices)
   devicesMap[device.name] = device;
-}
+
 
 export = devicesMap;