[RUMF-848] add a ESLint rule to enforce declarative modules

Author: BenoitZugmeyer

.eslintrc.js

@@ -21,8 +21,10 @@ module.exports = {
     'eslint-plugin-prefer-arrow',
     'eslint-plugin-unicorn',
     '@typescript-eslint',
+    'eslint-plugin-local-rules',
   ],
   rules: {
+    'local-rules/disallow-potential-side-effects': 'error',
     '@typescript-eslint/array-type': ['error', { default: 'array-simple' }],
     '@typescript-eslint/ban-ts-comment': [
       'error',

LICENSE-3rdparty.csv

@@ -29,8 +29,9 @@ dev,emoji-name-map,MIT,Copyright 2016-19 Ionică Bizău <bizauionica@gmail.com>
 dev,eslint,MIT,Copyright JS Foundation and other contributors
 dev,eslint-config-prettier,MIT,Copyright (c) 2017, 2018, 2019, 2020 Simon Lydell and contributors
 dev,eslint-plugin-import,MIT,Copyright (c) 2015 Ben Mosher
-dev,eslint-plugin-jsdoc,BSD-3-Clause,Copyright (c) 2018, Gajus Kuizinas (http://gajus.com/)
 dev,eslint-plugin-jasmine,MIT,Copyright (c) 2021 Tom Vincent
+dev,eslint-plugin-jsdoc,BSD-3-Clause,Copyright (c) 2018, Gajus Kuizinas (http://gajus.com/)
+dev,eslint-plugin-local-rules,MIT,Copyright (c) 2017 Clayton Watts
 dev,eslint-plugin-prefer-arrow,MIT,Copyright (c) 2018 Triston Jones
 dev,eslint-plugin-unicorn,MIT,Copyright (c) Sindre Sorhus <sindresorhus@gmail.com> (https://sindresorhus.com)
 dev,express,MIT,Copyright 2009-2014 TJ Holowaychuk 2013-2014 Roman Shtylman 2014-2015 Douglas Christopher Wilson

eslint-local-rules.js

@@ -0,0 +1,110 @@
+/* eslint-disable unicorn/filename-case */
+const path = require('path')
+
+module.exports = {
+  'disallow-potential-side-effects': {
+    meta: {
+      docs: {
+        description: 'Disallow potential side effects in types, constants and internal files',
+        recommended: false,
+      },
+      schema: [],
+    },
+    create(context) {
+      const filename = path.basename(context.getFilename())
+      const dotIndex = filename.lastIndexOf('.')
+      const filenameWithoutExtension = dotIndex < 0 ? filename : filename.slice(0, dotIndex)
+      if (!isRestrictedFile(filenameWithoutExtension)) {
+        return {}
+      }
+      return {
+        Program(node) {
+          node.body.forEach((child) => {
+            reportRestrictedDeclarations(context, child)
+          })
+        },
+      }
+    },
+  },
+}
+
+function isRestrictedFile(filenameWithoutExtension) {
+  return (
+    filenameWithoutExtension === 'types' ||
+    filenameWithoutExtension === 'internal' ||
+    filenameWithoutExtension === 'constants' ||
+    filenameWithoutExtension.endsWith('.constants') ||
+    filenameWithoutExtension.endsWith('.types')
+  )
+}
+
+function reportRestrictedDeclarations(context, node) {
+  switch (node.type) {
+    case 'TemplateLiteral':
+      node.expressions.forEach((child) => reportRestrictedDeclarations(context, child))
+      break
+    case 'ExportNamedDeclaration':
+    case 'ExportAllDeclaration':
+    case 'ImportDeclaration':
+      if (node.declaration) {
+        reportRestrictedDeclarations(context, node.declaration)
+      } else if (node.source && !isRestrictedFile(path.basename(node.source.value))) {
+        context.report({
+          node: node.source,
+          message: `This file can only import types, constants and internal files`,
+        })
+      }
+      break
+    case 'VariableDeclaration':
+      node.declarations.forEach((child) => reportRestrictedDeclarations(context, child))
+      break
+    case 'VariableDeclarator':
+      if (node.init) {
+        reportRestrictedDeclarations(context, node.init)
+      }
+      break
+    case 'ArrayExpression':
+      node.elements.forEach((child) => reportRestrictedDeclarations(context, child))
+      break
+    case 'UnaryExpression':
+      reportRestrictedDeclarations(context, node.argument)
+      break
+    case 'ObjectExpression':
+      node.properties.forEach((child) => reportRestrictedDeclarations(context, child))
+      break
+    case 'SpreadElement':
+      reportRestrictedDeclarations(context, node.argument)
+      break
+    case 'Property':
+      reportRestrictedDeclarations(context, node.key)
+      reportRestrictedDeclarations(context, node.value)
+      break
+    case 'AssignmentExpression':
+    case 'BinaryExpression':
+      reportRestrictedDeclarations(context, node.left)
+      reportRestrictedDeclarations(context, node.right)
+      break
+    case 'TSAsExpression':
+    case 'ExpressionStatement':
+      reportRestrictedDeclarations(context, node.expression)
+      break
+    case 'MemberExpression':
+      reportRestrictedDeclarations(context, node.object)
+      reportRestrictedDeclarations(context, node.property)
+      break
+    case 'FunctionExpression':
+    case 'ArrowFunctionExpression':
+    case 'FunctionDeclaration':
+    case 'ClassDeclaration':
+    case 'TSEnumDeclaration':
+    case 'TSInterfaceDeclaration':
+    case 'TSTypeAliasDeclaration':
+    case 'TSDeclareFunction':
+    case 'Literal':
+    case 'Identifier':
+      break
+    default:
+      context.report({ node, message: `${node.type} not allowed in types, constants and internal files` })
+      break
+  }
+}

package.json

@@ -53,6 +53,7 @@
     "eslint-plugin-import": "2.22.1",
     "eslint-plugin-jasmine": "4.1.2",
     "eslint-plugin-jsdoc": "30.7.13",
+    "eslint-plugin-local-rules": "1.0.1",
     "eslint-plugin-prefer-arrow": "1.2.2",
     "eslint-plugin-unicorn": "25.0.1",
     "express": "4.17.1",

tsconfig.json

@@ -4,6 +4,6 @@
   "compilerOptions": {
     "types": ["jasmine"]
   },
-  "include": ["packages", "scripts", "test", ".eslintrc.js"],
+  "include": ["packages", "scripts", "test", ".eslintrc.js", "eslint-local-rules.js"],
   "exclude": ["packages/*/cjs", "packages/*/esm", "packages/*/bundle", "test/e2e", "test/app"]
 }

yarn.lock

@@ -4268,6 +4268,11 @@ eslint-plugin-jsdoc@30.7.13:
     semver "^7.3.4"
     spdx-expression-parse "^3.0.1"
 
+eslint-plugin-local-rules@1.0.1:
+  version "1.0.1"
+  resolved "https://registry.yarnpkg.com/eslint-plugin-local-rules/-/eslint-plugin-local-rules-1.0.1.tgz#1a1f2659ad9297ea82a469d1f5b92b26d90ea3b0"
+  integrity sha512-spxkMBos6/ekNxO7khP2zj0j+tdNIhc3GWjXX397L/5R4ZM5huAIks6ADlZVRyiyUKbo/ABJgH/iP6cu9YYnyg==
+
 eslint-plugin-prefer-arrow@1.2.2:
   version "1.2.2"
   resolved "https://registry.yarnpkg.com/eslint-plugin-prefer-arrow/-/eslint-plugin-prefer-arrow-1.2.2.tgz#0c6d25a6b94cb3e0110a23d129760af5860edb6e"