Adding basing setup for eslint

.eslintignore

@@ -0,0 +1,11 @@
+# Exclude everything, and use an allowlist to include just the folders we want checked.
+/*
+!/app
+!/test
+!/plugins
+!/buildtools
+!/.eslintrc.js
+
+# And exclude some things within those (generated files)
+/_build
+/plugins/**/dist

.eslintrc.js

@@ -0,0 +1,122 @@
+module.exports = {
+  // Basic settings for JS files.
+  extends: ['eslint:recommended'],
+  env: {
+    node: true,
+    es6: true,
+  },
+  // Set parser to support, e.g. import() function for dynamic imports (see
+  // https://stackoverflow.com/a/47833471/328565 and https://stackoverflow.com/a/69557309/328565).
+  parser: '@babel/eslint-parser',
+  parserOptions: {
+    ecmaVersion: 2018,
+    requireConfigFile: false,
+  },
+  ignorePatterns: [
+    "/static/**/*.js",        // Built JS bundles
+    "*-ti.ts",                // Files generated by ts-interface-builder
+  ],
+  rules: {
+    'no-unused-vars': ["error", {args: "none"}],
+    'no-prototype-builtins': 'off',
+    'no-trailing-spaces': 'warn',
+    'comma-spacing': 'warn',
+    'semi-spacing': 'warn',
+  },
+
+  // The Typescript-specific settings apply only to TS files. ESLint is expensive here, and has to
+  // analyze dependencies for type-checking. (In an editor, it's much faster when used with
+  // tsserver.)
+  overrides: [{
+    files: "**/*.ts",
+    extends: [
+      'eslint:recommended',
+      'plugin:@typescript-eslint/recommended',
+      'plugin:@typescript-eslint/recommended-requiring-type-checking',
+    ],
+    parser: "@typescript-eslint/parser",
+    plugins: ["@typescript-eslint"],
+    parserOptions: {
+      tsconfigRootDir: __dirname,
+      project: ['./tsconfig.eslint.json'],
+      sourceType: 'module',
+      ecmaVersion: 2018,
+    },
+    env: {
+      node: true,
+      browser: true,
+      es6: true,
+      mocha: true,
+    },
+    globals: {
+      Promise: true
+    },
+    rules: {
+      // A lot of the options below would be helpful to keep on, but would need a lot of fix-ups.
+      "@typescript-eslint/ban-types": 'off',
+      "@typescript-eslint/explicit-member-accessibility": ["error", {overrides: {constructors: 'off'}}],
+      "@typescript-eslint/explicit-module-boundary-types": 'off',
+      // These settings mimic what we had before with tslint.
+      "@typescript-eslint/member-ordering": ["warn", {default: [
+        'public-static-field',
+        'public-static-method',
+        'protected-static-field', 'private-static-field', 'static-field',
+        'protected-static-method', 'private-static-method', 'static-method',
+        'public-field', 'protected-field', 'private-field', 'field',
+        'public-constructor', 'protected-constructor', 'private-constructor', 'constructor',
+        'public-method', 'protected-method', 'private-method', 'method',
+      ]}],
+      "@typescript-eslint/naming-convention": ["warn", {
+        selector: "memberLike", filter: { match: false, regex: '(listenTo)' },
+        modifiers: ["private"], format: ["camelCase"], leadingUnderscore: "require"
+      }],
+      "@typescript-eslint/no-empty-function": 'off',
+      "@typescript-eslint/no-explicit-any": 'off',
+      "@typescript-eslint/no-inferrable-types": 'off',
+      "@typescript-eslint/no-misused-promises": ["error", {"checksVoidReturn": false}],
+      "@typescript-eslint/no-namespace": 'off',
+      "@typescript-eslint/no-non-null-assertion": 'off',
+      "@typescript-eslint/no-shadow": ["warn", { ignoreTypeValueShadow: true }],
+      "@typescript-eslint/no-this-alias": 'off',
+      "@typescript-eslint/no-type-alias": ["warn", {
+        "allowAliases": "always",
+        "allowCallbacks": "always",
+        "allowConditionalTypes": "always",
+        "allowConstructors": "always",
+        "allowLiterals": "in-unions-and-intersections",
+        "allowMappedTypes": "always",
+        "allowTupleTypes": "always",
+        "allowGenerics": "always",
+      }],
+      "@typescript-eslint/no-unsafe-assignment": 'off',
+      "@typescript-eslint/no-unsafe-argument": 'off',
+      "@typescript-eslint/no-unsafe-call": 'off',
+      "@typescript-eslint/no-unsafe-member-access": 'off',
+      "@typescript-eslint/no-unsafe-return": 'off',
+      "@typescript-eslint/no-unused-vars": ["error", { "vars": "all", "args": "none", "ignoreRestSiblings": false }],
+      "@typescript-eslint/no-var-requires": 'off',
+      "@typescript-eslint/prefer-regexp-exec": 'off',
+      "@typescript-eslint/require-await": 'off',
+      "@typescript-eslint/restrict-plus-operands": 'off',
+      "@typescript-eslint/restrict-template-expressions": 'off',
+      "@typescript-eslint/type-annotation-spacing": 'warn',
+      "@typescript-eslint/unbound-method": 'off',
+      'no-undef': 'off',
+      'no-prototype-builtins': 'off',
+      'prefer-rest-params': 'off',
+      'no-console': 'off',
+      'no-shadow': 'off',
+      'no-inner-declarations': 'off',
+      'max-len': ['warn', {code: 120, ignoreUrls: true}],
+      'sort-imports': ['warn', {ignoreDeclarationSort: true, ignoreCase: true, allowSeparatedGroups: true}],
+      'no-trailing-spaces': 'warn',
+      'no-unused-expressions': ["error", {allowShortCircuit: true, allowTernary: true}],
+
+      'block-spacing': ['warn', 'always'],
+      'comma-spacing': 'warn',
+      'curly': ['warn', 'all'],
+      'semi': ['warn', 'always'],
+      'semi-spacing': 'warn',
+    },
+  }]
+}

package.json

@@ -21,6 +21,8 @@
     "test:docker": "./test/test_under_docker.sh",
     "test:python": "sandbox_venv3/bin/python sandbox/grist/runtests.py ${GREP_TESTS:+discover -p \"test*${GREP_TESTS}*.py\"}",
     "cli": "NODE_PATH=_build:_build/stubs:_build/ext node _build/app/server/companion.js",
+    "lint": "eslint .",
+    "lint:fix": "eslint --fix .",
     "generate:translation": "NODE_PATH=_build:_build/stubs:_build/ext node buildtools/generate_translation_keys.js"
   },
   "keywords": [
@@ -34,6 +36,8 @@
   },
   "private": false,
   "devDependencies": {
+    "@babel/core": "7.18.5",
+    "@babel/eslint-parser": "7.18.2",
     "@types/accept-language-parser": "1.5.2",
     "@types/backbone": "1.3.43",
     "@types/chai": "4.1.7",
@@ -71,12 +75,15 @@
     "@types/uuid": "3.4.4",
     "@types/which": "2.0.1",
     "@types/ws": "^6",
+    "@typescript-eslint/eslint-plugin": "5.29.0",
+    "@typescript-eslint/parser": "5.29.0",
     "app-module-path": "2.2.0",
     "catw": "1.0.1",
     "chai": "4.2.0",
     "chai-as-promised": "7.1.1",
     "chance": "1.0.16",
     "esbuild-loader": "2.19.0",
+    "eslint": "8.18.0",
     "http-proxy": "1.18.1",
     "i18next-scanner": "4.1.0",
     "jsdom": "16.5.0",

tsconfig.eslint.json

@@ -0,0 +1,13 @@
+{
+  "extends": "./buildtools/tsconfig-base.json",
+  "include": [
+    "app/**/*.js",
+    "app/**/*.ts",
+    "test/**/*.js",
+    "test/**/*.ts",
+    "plugins/**/*.js",
+    "plugins/**/*.ts",
+    "buildtools/**/*.js",
+    "buildtools/**/*.ts",
+  ]
+}