added dictionary rule eslint

Author: l-trotta

specification/eslint.config.js

@@ -32,6 +32,7 @@ export default defineConfig({
   plugins: { 'es-spec-validator': validator },
   rules: {
     'es-spec-validator/single-key-dictionary-key-is-string': 'error',
+    'es-spec-validator/dictionary-key-is-string': 'error',
     'es-spec-validator/invalid-node-types': 'warn'
   }
 })

validator/README.md

@@ -8,6 +8,7 @@ It is configured [in the specification directory](../specification/eslint.config
 | Name | Description |
 | - | - |
 | `single-key-dictionary-key-is-string` | `SingleKeyDictionary` keys must be strings. |
+| `dictionary-key-is-string` | `Dictionary` keys must be strings. |
 | `invalid-node-types` | The spec uses a subset of TypeScript, so some types, clauses and expressions are not allowed. |
 
 ## Usage

validator/eslint-plugin-es-spec.js

@@ -17,11 +17,13 @@
  * under the License.
  */
 import singleKeyDict from './rules/single-key-dictionary-key-is-string.js'
+import Dict from './rules/dictionary-key-is-string.js'
 import invalidNodeTypes from './rules/invalid-node-types.js'
 
 export default {
   rules: {
     'single-key-dictionary-key-is-string': singleKeyDict,
+    'dictionary-key-is-string': Dict,
     'invalid-node-types': invalidNodeTypes,
   }
 }

validator/rules/dictionary-key-is-string.js

@@ -0,0 +1,64 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+import { ESLintUtils } from '@typescript-eslint/utils';
+import ts from 'typescript'
+
+const createRule = ESLintUtils.RuleCreator(name => `https://example.com/rule/${name}`)
+
+export default createRule({
+  name: 'dictionary-key-is-string',
+  create(context) {
+    return {
+      TSTypeReference(node) {
+        if (node.typeName.name === 'Dictionary') {
+          const key = node.typeArguments.params[0]
+          switch (key.type) {
+            case 'TSTypeReference':
+              // trace the reference to its original type definition
+              const services = ESLintUtils.getParserServices(context)
+              const type = services.getTypeAtLocation(key)
+
+              // check that the type is a string or an enum (enum members evaluate to strings)
+              if (type.intrinsicName !== 'string' && !(type.symbol?.flags & ts.SymbolFlags.RegularEnum)) {
+                context.report({ node, messageId: 'stringKey' })
+              }
+              break
+            case 'TSStringKeyword':
+              // type is string, skip
+              break
+            default:
+              // unknown type!
+              context.report({ node, messageId: 'stringKey' })
+              break
+          }
+        }
+      },
+    }
+  },
+  meta: {
+    docs: {
+      description: 'Dictionary keys must be strings',
+    },
+    messages: {
+      stringKey: "Dictionary's key must be a string"
+    },
+    type: 'suggestion',
+  },
+  defaultOptions: []
+})