refactor: include create-testing-library-rule

Author: Belco90

lib/create-testing-library-rule.ts

@@ -0,0 +1,37 @@
+import { ESLintUtils, TSESLint } from '@typescript-eslint/experimental-utils';
+import { getDocsUrl } from './utils';
+import {
+  detectTestingLibraryUtils,
+  DetectionHelpers,
+} from './detect-testing-library-utils';
+
+type CreateRuleMetaDocs = Omit<TSESLint.RuleMetaDataDocs, 'url'>;
+type CreateRuleMeta<TMessageIds extends string> = {
+  docs: CreateRuleMetaDocs;
+} & Omit<TSESLint.RuleMetaData<TMessageIds>, 'docs'>;
+
+export function createTestingLibraryRule<
+  TOptions extends readonly unknown[],
+  TMessageIds extends string,
+  TRuleListener extends TSESLint.RuleListener = TSESLint.RuleListener
+>(
+  config: Readonly<{
+    name: string;
+    meta: CreateRuleMeta<TMessageIds>;
+    defaultOptions: Readonly<TOptions>;
+    create: (
+      context: Readonly<TSESLint.RuleContext<TMessageIds, TOptions>>,
+      optionsWithDefault: Readonly<TOptions>,
+      detectionHelpers: Readonly<DetectionHelpers>
+    ) => TRuleListener;
+  }>
+) {
+  const { create, ...remainingConfig } = config;
+
+  return ESLintUtils.RuleCreator(getDocsUrl)({
+    ...remainingConfig,
+    create: detectTestingLibraryUtils<TOptions, TMessageIds, TRuleListener>(
+      create
+    ),
+  });
+}

lib/detect-testing-library-utils.ts

@@ -0,0 +1,65 @@
+import { TSESLint, TSESTree } from '@typescript-eslint/experimental-utils';
+
+export type DetectionHelpers = {
+  getIsImportingTestingLibrary: () => boolean;
+};
+
+/**
+ * Enhances a given rule `create` with helpers to detect Testing Library utils.
+ */
+export function detectTestingLibraryUtils<
+  TOptions extends readonly unknown[],
+  TMessageIds extends string,
+  TRuleListener extends TSESLint.RuleListener = TSESLint.RuleListener
+>(
+  ruleCreate: (
+    context: Readonly<TSESLint.RuleContext<TMessageIds, TOptions>>,
+    optionsWithDefault: Readonly<TOptions>,
+    detectionHelpers: Readonly<DetectionHelpers>
+  ) => TRuleListener
+) {
+  return (
+    context: Readonly<TSESLint.RuleContext<TMessageIds, TOptions>>,
+    optionsWithDefault: Readonly<TOptions>
+  ): TRuleListener => {
+    let isImportingTestingLibrary = false;
+
+    // TODO: init here options based on shared ESLint config
+
+    // helpers for Testing Library detection
+    const helpers: DetectionHelpers = {
+      getIsImportingTestingLibrary() {
+        return isImportingTestingLibrary;
+      },
+    };
+
+    // instructions for Testing Library detection
+    const detectionInstructions: TSESLint.RuleListener = {
+      ImportDeclaration(node: TSESTree.ImportDeclaration) {
+        isImportingTestingLibrary = /testing-library/g.test(
+          node.source.value as string
+        );
+      },
+    };
+
+    // update given rule to inject Testing Library detection
+    const ruleInstructions = ruleCreate(context, optionsWithDefault, helpers);
+    const enhancedRuleInstructions = Object.assign({}, ruleInstructions);
+
+    Object.keys(detectionInstructions).forEach((instruction) => {
+      (enhancedRuleInstructions as TSESLint.RuleListener)[instruction] = (
+        node
+      ) => {
+        if (instruction in detectionInstructions) {
+          detectionInstructions[instruction](node);
+        }
+
+        if (ruleInstructions[instruction]) {
+          return ruleInstructions[instruction](node);
+        }
+      };
+    });
+
+    return enhancedRuleInstructions;
+  };
+}