enforce presence of DocumentationTypes for type *Options or type *Result

eslint-local-rules/index.mjs

@@ -16,6 +16,7 @@ import {
   TVariablesShouldExtendOperationVariables,
   TDataTVariablesOrder,
 } from "./generics.ts";
+import { enforceDocumentationTypes } from "./namespace-documentationTypes.ts";
 
 export default {
   "require-using-disposable": requireUsingDisposable,
@@ -31,4 +32,5 @@ export default {
   "variables-should-extend-operation-variables":
     TVariablesShouldExtendOperationVariables,
   "tdata-tvariables-order": TDataTVariablesOrder,
+  "enforce-documentation-types": enforceDocumentationTypes,
 };

eslint-local-rules/namespace-documentationTypes.ts

@@ -0,0 +1,72 @@
+import type { TSESTree as AST } from "@typescript-eslint/types";
+import { ESLintUtils } from "@typescript-eslint/utils";
+
+export const enforceDocumentationTypes = ESLintUtils.RuleCreator.withoutDocs({
+  create(context) {
+    const namespaces = [];
+    const shouldBeDocumented: Record<
+      string,
+      {
+        namespaces: string[];
+        node: AST.TSTypeAliasDeclaration;
+      }
+    > = {};
+    return {
+      TSModuleDeclaration(node) {
+        if (node.kind !== "namespace") {
+          return;
+        }
+        namespaces.push(
+          node.id.type === "Identifier" ? node.id.name : "<unknown>"
+        );
+      },
+      "TSModuleDeclaration:exit"(node) {
+        if (node.kind !== "namespace") {
+          return;
+        }
+        namespaces.pop();
+        for (const [name, entry] of Object.entries(shouldBeDocumented)) {
+          if (entry.namespaces.length > namespaces.length) {
+            delete shouldBeDocumented[name];
+            context.report({
+              node: entry.node.id,
+              messageId: "shouldBeDocumented",
+            });
+          }
+        }
+      },
+      ExportNamedDeclaration(node) {
+        if (!node.declaration) {
+          return;
+        }
+        if (node.declaration.type === "TSTypeAliasDeclaration") {
+          const name = node.declaration.id.name;
+          if (name.endsWith("Result") || name.endsWith("Options")) {
+            shouldBeDocumented[name] = {
+              node: node.declaration,
+              namespaces: [...namespaces],
+            };
+          }
+        } else if (node.declaration.type === "TSInterfaceDeclaration") {
+          const name = node.declaration.id.name;
+          if (
+            name in shouldBeDocumented &&
+            namespaces.at(-1) === "DocumentationTypes"
+          ) {
+            delete shouldBeDocumented[name];
+          }
+        }
+      },
+    };
+  },
+  meta: {
+    messages: {
+      shouldBeDocumented:
+        "This type should have an interface with the same name in a nested `DocumentationTypes` namespace.",
+    },
+    type: "problem",
+    schema: [],
+    fixable: "code",
+  },
+  defaultOptions: [],
+});

eslint.config.mjs

@@ -201,6 +201,7 @@ export default [
       "local-rules/valid-inherit-doc": "error",
       "local-rules/variables-should-extend-operation-variables": "error",
       "local-rules/tdata-tvariables-order": "error",
+      "local-rules/enforce-documentation-types": "error",
     },
   },
   ...compat.extends("plugin:testing-library/react").map((config) => ({