chore(prefer-todo): migrate to TS (#335)

Author: G-Rath

src/rules/__tests__/prefer-todo.test.js renamed to src/rules/__tests__/prefer-todo.test.ts

@@ -1,7 +1,7 @@
-import { RuleTester } from 'eslint';
+import { TSESLint } from '@typescript-eslint/experimental-utils';
 import rule from '../prefer-todo';
 
-const ruleTester = new RuleTester({
+const ruleTester = new TSESLint.RuleTester({
   parserOptions: { ecmaVersion: 2015 },
 });
 

src/rules/prefer-todo.js

@@ -0,0 +1,119 @@
+import {
+  AST_NODE_TYPES,
+  TSESLint,
+  TSESTree,
+} from '@typescript-eslint/experimental-utils';
+import {
+  FunctionExpression,
+  JestFunctionCallExpression,
+  StringLiteral,
+  TestCaseName,
+  createRule,
+  getNodeName,
+  isFunction,
+  isStringNode,
+  isTestCase,
+} from './tsUtils';
+
+function isOnlyTestTitle(node: TSESTree.CallExpression) {
+  return node.arguments.length === 1;
+}
+
+function isFunctionBodyEmpty(node: FunctionExpression) {
+  /* istanbul ignore next https://github.com/typescript-eslint/typescript-eslint/issues/734 */
+  if (!node.body) {
+    throw new Error(
+      `Unexpected null while performing prefer-todo - please file a github issue at https://github.com/jest-community/eslint-plugin-jest`,
+    );
+  }
+
+  return (
+    node.body.type === AST_NODE_TYPES.BlockStatement &&
+    node.body.body &&
+    !node.body.body.length
+  );
+}
+
+function isTestBodyEmpty(node: TSESTree.CallExpression) {
+  const [, fn] = node.arguments;
+  return fn && isFunction(fn) && isFunctionBodyEmpty(fn);
+}
+
+function addTodo(
+  node: JestFunctionCallExpression<TestCaseName>,
+  fixer: TSESLint.RuleFixer,
+) {
+  const testName = getNodeName(node.callee)
+    .split('.')
+    .shift();
+  return fixer.replaceText(node.callee, `${testName}.todo`);
+}
+
+interface CallExpressionWithStringArgument extends TSESTree.CallExpression {
+  arguments: [StringLiteral | TSESTree.TemplateLiteral];
+}
+
+function isFirstArgString(
+  node: TSESTree.CallExpression,
+): node is CallExpressionWithStringArgument {
+  return node.arguments[0] && isStringNode(node.arguments[0]);
+}
+
+const isTargetedTestCase = (
+  node: TSESTree.CallExpression,
+): node is JestFunctionCallExpression<TestCaseName> =>
+  isTestCase(node) &&
+  (['it', 'test', 'it.skip', 'test.skip'] as Array<string | null>).includes(
+    getNodeName(node.callee),
+  );
+
+export default createRule({
+  name: __filename,
+  meta: {
+    docs: {
+      category: 'Best Practices',
+      description: 'Suggest using `test.todo`',
+      recommended: false,
+    },
+    messages: {
+      todoOverEmpty: 'Prefer todo test case over empty test case',
+      todoOverUnimplemented:
+        'Prefer todo test case over unimplemented test case',
+    },
+    fixable: 'code',
+    schema: [],
+    type: 'layout',
+  },
+  defaultOptions: [],
+  create(context) {
+    return {
+      CallExpression(node) {
+        if (!isTargetedTestCase(node) || !isFirstArgString(node)) {
+          return;
+        }
+
+        if (isTestBodyEmpty(node)) {
+          context.report({
+            messageId: 'todoOverEmpty',
+            node,
+            fix: fixer => [
+              fixer.removeRange([
+                node.arguments[0].range[1],
+                node.arguments[1].range[1],
+              ]),
+              addTodo(node, fixer),
+            ],
+          });
+        }
+
+        if (isOnlyTestTitle(node)) {
+          context.report({
+            messageId: 'todoOverUnimplemented',
+            node,
+            fix: fixer => [addTodo(node, fixer)],
+          });
+        }
+      },
+    };
+  },
+});

src/rules/prefer-todo.ts

@@ -127,7 +127,13 @@ export type JestFunctionCallExpression<
   | JestFunctionCallExpressionWithMemberExpressionCallee<FunctionName>
   | JestFunctionCallExpressionWithIdentifierCallee<FunctionName>;
 
-export const getNodeName = (node: TSESTree.Node): string | null => {
+export function getNodeName(
+  node:
+    | JestFunctionMemberExpression<JestFunctionName>
+    | JestFunctionIdentifier<JestFunctionName>,
+): string;
+export function getNodeName(node: TSESTree.Node): string | null;
+export function getNodeName(node: TSESTree.Node): string | null {
   function joinNames(a?: string | null, b?: string | null): string | null {
     return a && b ? `${a}.${b}` : null;
   }
@@ -145,7 +151,7 @@ export const getNodeName = (node: TSESTree.Node): string | null => {
   }
 
   return null;
-};
+}
 
 export type FunctionExpression =
   | TSESTree.ArrowFunctionExpression
@@ -192,6 +198,27 @@ export const isLiteralNode = (node: {
   type: AST_NODE_TYPES;
 }): node is TSESTree.Literal => node.type === AST_NODE_TYPES.Literal;
 
+export interface StringLiteral extends TSESTree.Literal {
+  value: string;
+}
+
+export type StringNode = StringLiteral | TSESTree.TemplateLiteral;
+
+export const isStringLiteral = (node: TSESTree.Node): node is StringLiteral =>
+  node.type === AST_NODE_TYPES.Literal && typeof node.value === 'string';
+
+export const isTemplateLiteral = (
+  node: TSESTree.Node,
+): node is TSESTree.TemplateLiteral =>
+  node && node.type === AST_NODE_TYPES.TemplateLiteral;
+
+export const isStringNode = (node: TSESTree.Node): node is StringNode =>
+  isStringLiteral(node) || isTemplateLiteral(node);
+
+/* istanbul ignore next we'll need this later */
+export const getStringValue = (arg: StringNode): string =>
+  isTemplateLiteral(arg) ? arg.quasis[0].value.raw : arg.value;
+
 const collectReferences = (scope: TSESLint.Scope.Scope) => {
   const locals = new Set();
   const unresolved = new Set();

src/rules/tsUtils.ts

@@ -101,21 +101,6 @@ const describeAliases = new Set(['describe', 'fdescribe', 'xdescribe']);
 
 const testCaseNames = new Set(['fit', 'it', 'test', 'xit', 'xtest']);
 
-export const getNodeName = node => {
-  function joinNames(a, b) {
-    return a && b ? `${a}.${b}` : null;
-  }
-
-  switch (node && node.type) {
-    case 'Identifier':
-      return node.name;
-    case 'MemberExpression':
-      return joinNames(getNodeName(node.object), getNodeName(node.property));
-  }
-
-  return null;
-};
-
 export const isTestCase = node =>
   node &&
   node.type === 'CallExpression' &&
@@ -165,11 +150,3 @@ export const getDocsUrl = filename => {
 
   return `${REPO_URL}/blob/v${version}/docs/rules/${ruleName}.md`;
 };
-
-export function composeFixers(node) {
-  return (...fixers) => {
-    return fixerApi => {
-      return fixers.reduce((all, fixer) => [...all, fixer(node, fixerApi)], []);
-    };
-  };
-}