Merge pull request #1 from lauriharpf/add-typescript-eslint

Add typescript-eslint

.eslintignore

@@ -0,0 +1,8 @@
+# don't ever lint node_modules
+node_modules
+# don't lint build output
+build
+# don't lint nyc coverage output
+coverage
+# don't lint the eslint config (https://stackoverflow.com/a/60840108/843984)
+.eslintrc.js

.eslintrc.js

@@ -0,0 +1,31 @@
+module.exports = {
+  root: true,
+  parser: "@typescript-eslint/parser",
+  parserOptions: {
+    project: ["./tsconfig.json"],
+    ecmaVersion: 2020,
+    sourceType: "module",
+    tsconfigRootDir: __dirname,
+  },
+  plugins: ["jest"],
+  extends: [
+    "eslint:recommended",
+    "plugin:@typescript-eslint/recommended",
+    "plugin:@typescript-eslint/recommended-requiring-type-checking",
+  ],
+  env: { node: true },
+  overrides: [
+    {
+      files: ["*.test.ts", "test/**"],
+      plugins: ["jest"],
+      rules: {
+        // Turn off unbound method rule but *only* for test files (https://github.com/jest-community/eslint-plugin-jest/blob/main/docs/rules/unbound-method.md)
+        "@typescript-eslint/unbound-method": "off",
+        "jest/unbound-method": "error",
+      },
+    },
+  ],
+  rules: {
+    "@typescript-eslint/unbound-method": "error",
+  },
+};

README.md

@@ -23,7 +23,11 @@ query Posts {
 
 6. `CTRL-C` stops the server
 
-Tests can be run with `npm test` (`npm test -- --coverage` to report code coverage)
+### Other commands
+
+- `npm test` to run tests
+- `npm test -- --coverage` to run tests and collect code coverage
+- `npm run lint` to lint the project
 
 ## Template contents
 
@@ -33,6 +37,7 @@ Tests can be run with `npm test` (`npm test -- --coverage` to report code covera
 - Example resolvers and [Apollo REST Data Source](https://www.npmjs.com/package/apollo-datasource-rest)s (posts, users)
 - Test infrastructure ([ts-jest](https://github.com/kulshekhar/ts-jest), [apollo-server-testing](https://www.apollographql.com/docs/apollo-server/testing/testing/) and [nock](https://www.npmjs.com/package/nock)) and example tests
 - [ts-node-dev](https://www.npmjs.com/package/ts-node-dev) for development (restarts app when code changes)
+- [typescript-eslint](https://github.com/typescript-eslint/typescript-eslint/blob/master/docs/getting-started/linting/README.md) with [type-aware rules](https://github.com/typescript-eslint/typescript-eslint/blob/master/docs/getting-started/linting/TYPED_LINTING.md)
 - Github: Dependabot dependency updates
 
 ## Customizing for your project