Migrate to typescript

.eslintrc

@@ -1,19 +1,28 @@
 {
   "extends": [
     "mourner",
-    "plugin:flowtype/recommended",
-    "plugin:import/recommended"
+    "plugin:import/recommended",
+    "plugin:import/typescript"
   ],
-  "parser": "babel-eslint",
+  "parser": "@typescript-eslint/parser",
   "parserOptions": {
-    "sourceType": "module"
+    "sourceType": "module",
+    "createDefaultProgram": true
   },
   "plugins": [
-    "flowtype",
+    "@typescript-eslint",
     "import",
     "jsdoc"
   ],
   "rules": {
+    "no-dupe-class-members": "off",
+    "@typescript-eslint/no-dupe-class-members": ["error"],
+    "@typescript-eslint/no-unused-vars": [
+      "warn",
+      { "argsIgnorePattern": "^_" }
+    ],
+    // Disable no-undef. It's covered by @typescript-eslint
+    "no-undef": "off",
     // temporarily disabled due to https://github.com/babel/babel-eslint/issues/485
     "no-use-before-define": "off",
 
@@ -33,13 +42,6 @@
 
     "array-bracket-spacing": "off",
     "consistent-return": "off",
-    "flowtype/define-flow-type": 1,
-    "flowtype/require-valid-file-annotation": [
-      2,
-      "always", {
-        "annotationStyle": "line"
-      }
-    ],
     "global-require": "off",
     "import/no-commonjs": "error",
     "key-spacing": "off",
@@ -50,7 +52,7 @@
         "object": "Object",
         "property": "assign"
     }],
-    "no-unused-vars": ["error", {"argsIgnorePattern": "^_$"}],
+    "no-unused-vars": "off",
     "no-warning-comments": "error",
     "object-curly-spacing": ["error", "never"],
     "prefer-arrow-callback": "error",
@@ -72,7 +74,7 @@
         "parameters": "off"
       }
     }],
-    "no-multiple-empty-lines": [ "error", { 
+    "no-multiple-empty-lines": [ "error", {
         "max": 1
     }],
     "jsdoc/check-param-names": "warn",
@@ -87,6 +89,7 @@
       "ignorePrivate": true
     }
   },
+  "ignorePatterns": ["build/*.js", "*.json"],
   "overrides": [
     {
       "files": ["debug/**", "bench/**", "test/**", "src/style-spec/**"],

.github/workflows/analyze.yml

@@ -18,12 +18,12 @@ jobs:
       # report status back to pull request
       - uses: haya14busa/action-workflow_run-status@v1
       - uses: actions/checkout@v2
-      - name: Use Node.js 10 x64
+      - name: Use Node.js 14 x64
         uses: actions/setup-node@v2-beta
         with:
-          node-version: 10
+          node-version: 14
           architecture: x64
-      - run: yarn install --frozen-lockfile
+      - run: npm ci
       - name: Download branch artifact
         uses: dawidd6/action-download-artifact@v2
         with: