chore(babel): add more language tests

packages/babel-preset-expo/CHANGELOG.md

@@ -17,6 +17,7 @@
 
 ### 💡 Others
 
+- Add more tests for obscure syntax used in Expo apps.
 - Remove unused peer dependency on `@babel/preset-env`. ([#27705](https://github.com/expo/expo/pull/27705) by [@EvanBacon](https://github.com/EvanBacon))
 - Disable color in snapshot tests in CI. ([#27301](https://github.com/expo/expo/pull/27301) by [@EvanBacon](https://github.com/EvanBacon))
 - Add additional tests for undefined platform minification behavior. ([#27515](https://github.com/expo/expo/pull/27515) by [@EvanBacon](https://github.com/EvanBacon))

packages/babel-preset-expo/src/__tests__/__snapshots__/compiler.test.ts.snap

@@ -0,0 +1,36 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`compiler allows destructuring in the catch block 1`] = `
+"Object.defineProperty(exports, "__esModule", { value: true });exports.App = App;var _jsxDevRuntime = require("react/jsx-dev-runtime");var _jsxFileName = "/Users/evanbacon/Documents/GitHub/expo/packages/babel-preset-expo/src/__tests__/samples/destructure-catch.tsx";function App() {
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  var foo = function () {
+    try {
+      console.log('hey');
+    } catch (_ref) {var message = _ref.message;
+      // NOTE(EvanBacon): React compiler throws:
+      // (BuildHIR::lowerAssignment) Could not find binding for declaration.
+      console.error(message);
+    }
+  };
+  return /*#__PURE__*/(0, _jsxDevRuntime.jsxDEV)("div", { children: "Hello" }, void 0, false, { fileName: _jsxFileName, lineNumber: 12, columnNumber: 10 }, this);
+}"
+`;
+
+exports[`compiler supports functions with discarded return values in try/catch blocks that run in memos 1`] = `
+"Object.defineProperty(exports, "__esModule", { value: true });exports.useSideEffectMayThrow = useSideEffectMayThrow;var _react = require("react");
+
+function SIDE_EFFECT_MAY_THROW() {}
+
+// NOTE(EvanBacon): React compiler throws:
+// Cannot read properties of undefined (reading 'preds')
+function useSideEffectMayThrow() {
+  return (0, _react.useMemo)(function () {
+    try {
+      SIDE_EFFECT_MAY_THROW();
+      return true;
+    } catch {
+      return false;
+    }
+  }, []);
+}"
+`;

packages/babel-preset-expo/src/__tests__/compiler.test.ts

@@ -0,0 +1,38 @@
+import * as babel from '@babel/core';
+import * as path from 'node:path';
+
+import preset from '..';
+
+function getCaller(props: Record<string, string | boolean>): babel.TransformCaller {
+  return props as unknown as babel.TransformCaller;
+}
+
+const options = {
+  caller: getCaller({ name: 'metro', engine: 'hermes', platform: 'ios', isDev: true }),
+  babelrc: false,
+  presets: [preset],
+  sourceMaps: false,
+
+  compact: false,
+  comments: true,
+  retainLines: true,
+};
+
+it(`allows destructuring in the catch block`, () => {
+  // Ensuring the transform doesn't throw.
+  const { code } = babel.transformFileSync(
+    path.resolve(__dirname, 'samples/destructure-catch.tsx'),
+    options
+  )!;
+
+  expect(code).toMatchSnapshot();
+});
+it(`supports functions with discarded return values in try/catch blocks that run in memos`, () => {
+  // Ensuring the transform doesn't throw.
+  const { code } = babel.transformFileSync(
+    path.resolve(__dirname, 'samples/try-catch-hook.tsx'),
+    options
+  )!;
+
+  expect(code).toMatchSnapshot();
+});

packages/babel-preset-expo/src/__tests__/samples/destructure-catch.tsx

@@ -0,0 +1,13 @@
+export function App() {
+  // eslint-disable-next-line @typescript-eslint/no-unused-vars
+  const foo = () => {
+    try {
+      console.log('hey');
+    } catch ({ message }) {
+      // NOTE(EvanBacon): React compiler throws:
+      // (BuildHIR::lowerAssignment) Could not find binding for declaration.
+      console.error(message);
+    }
+  };
+  return <div>Hello</div>;
+}

packages/babel-preset-expo/src/__tests__/samples/try-catch-hook.tsx

@@ -0,0 +1,16 @@
+import { useMemo } from 'react';
+
+function SIDE_EFFECT_MAY_THROW() {}
+
+// NOTE(EvanBacon): React compiler throws:
+// Cannot read properties of undefined (reading 'preds')
+export function useSideEffectMayThrow() {
+  return useMemo(() => {
+    try {
+      SIDE_EFFECT_MAY_THROW();
+      return true;
+    } catch {
+      return false;
+    }
+  }, []);
+}