fix(Example): add ESLint rule to enforce top-level component exports in SFT and CIT#3959
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fix(Example): add ESLint rule to enforce top-level component exports in SFT and CIT#3959
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also apply it to SFT and CIT
sgaczol
requested review from
Copilot,
kkafar,
kligarski,
kmichalikk and
t0maboro
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Pull request overview
This PR adds a local ESLint rule to enforce that top-level React component declarations in the single-feature-tests (SFT) and component-integration-tests (CIT) suites are exported, addressing Fast Refresh remounting caused by Metro module boundary heuristics.
Changes:
- Introduce a local ESLint plugin (
local-rules) with arequire-top-level-exportsrule. - Add ESLint configuration under
apps/src/teststo apply the rule to SFT and CIT. - Update SFT/CIT files to export their top-level components (e.g.,
ConfigScreen,TestScreen,HomeScreen, etc.).
Reviewed changes
Copilot reviewed 32 out of 32 changed files in this pull request and generated 2 comments.
Show a summary per file
| File | Description |
|---|---|
| apps/src/tests/single-feature-tests/tabs/test-tabs-tab-bar-minimize-behavior-ios/index.tsx | Export top-level tab test components. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-tab-bar-layout-direction/index.tsx | Export top-level config component. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-tab-bar-hidden/index.tsx | Export top-level config component. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-tab-bar-controller-mode-ios/index.tsx | Export top-level tab test components. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-tab-bar-color-scheme/index.tsx | Export top-level tab test components. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-stale-update-rejection.tsx | Export top-level components in the scenario. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-simple-nav.tsx | Export top-level components in the scenario. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-prevent-native-selection/index.tsx | Export top-level components in the scenario. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-more-navigation-controller.tsx | Export top-level components in the scenario. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-ime-insets.tsx | Export top-level config component. |
| apps/src/tests/single-feature-tests/tabs/test-tabs-appearance-defined-by-selected-tab.tsx | Export top-level tab screen component. |
| apps/src/tests/single-feature-tests/tabs/tabs-screen-orientation.tsx | Export top-level config component. |
| apps/src/tests/single-feature-tests/tabs/override-scroll-view-content-inset.tsx | Export top-level tab/content components. |
| apps/src/tests/single-feature-tests/tabs/bottom-accessory-layout.tsx | Export top-level accessory/config components. |
| apps/src/tests/single-feature-tests/stack-v5/test-stack-subviews-android/index.tsx | Export top-level stack setup/config components. |
| apps/src/tests/single-feature-tests/stack-v5/test-stack-simple-nav/index.tsx | Export top-level stack components/screens. |
| apps/src/tests/single-feature-tests/stack-v5/test-stack-back-button-android/index.tsx | Export top-level stack screens/controls. |
| apps/src/tests/single-feature-tests/stack-v5/test-animation-android.tsx | Export top-level stack screens/setup. |
| apps/src/tests/single-feature-tests/stack-v5/prevent-native-dismiss-single-stack.tsx | Export top-level stack screens/helpers. |
| apps/src/tests/single-feature-tests/stack-v5/prevent-native-dismiss-nested-stack.tsx | Export top-level nested stack screens/helpers. |
| apps/src/tests/single-feature-tests/stack-v4/stack-v4-orientation.tsx | Export top-level config component. |
| apps/src/tests/single-feature-tests/split/test-top-column-for-collapsing.tsx | Export top-level split column component. |
| apps/src/tests/single-feature-tests/split/test-command-show-column.tsx | Export top-level split column component. |
| apps/src/tests/single-feature-tests/scroll-view-marker/test-svm-configures-scroll-view.tsx | Export top-level content screen component. |
| apps/src/tests/single-feature-tests/index.tsx | Export top-level HomeScreen. |
| apps/src/tests/eslint-plugin-local-rules/require-top-level-exports.js | Implement local ESLint rule logic. |
| apps/src/tests/eslint-plugin-local-rules/package.json | Define local plugin package metadata. |
| apps/src/tests/eslint-plugin-local-rules/index.js | Export plugin rules entrypoint. |
| apps/src/tests/component-integration-tests/orientation/orientation-tabs-in-stack.tsx | Export top-level orientation test components. |
| apps/src/tests/component-integration-tests/orientation/orientation-stack-in-tabs.tsx | Export top-level orientation test components. |
| apps/src/tests/component-integration-tests/index.tsx | Export top-level HomeScreen. |
| apps/src/tests/.eslintrc.js | Apply local rule to SFT/CIT via overrides. |
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Comment on lines
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| if (stmt.type === 'VariableDeclaration' && stmt.declarations.length === 1) { | ||
| const decl = stmt.declarations[0]; | ||
| const name = decl.id?.name; | ||
| if ( | ||
| name && | ||
| isPascalCase(name) && | ||
| decl.init && | ||
| (decl.init.type === 'ArrowFunctionExpression' || | ||
| decl.init.type === 'FunctionExpression') | ||
| ) { | ||
| return name; | ||
| } | ||
| } |
Comment on lines
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| const path = require('path'); | ||
| const Module = require('module'); | ||
|
|
||
| const pluginPath = require.resolve( | ||
| path.join(__dirname, 'eslint-plugin-local-rules'), | ||
| ); | ||
| const originalResolve = Module._resolveFilename; | ||
| Module._resolveFilename = function (request, ...args) { | ||
| if (request === 'eslint-plugin-local-rules') { | ||
| return pluginPath; | ||
| } | ||
| return originalResolve.call(this, request, ...args); | ||
| }; | ||
|
|
kkafar
reviewed
May 4, 2026
Member
There was a problem hiding this comment.
I just took a peek at this PR, it's not a full review yet. My impression here is that this code is not test-related per se, it should not reside in apps/src/tests/ directory, apps/src/ will be fine.
What do you think?
cc @t0maboro
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Description
This PR introduces a local ESLint rule
require-top-level-exportsto ensure that all top-level React component declarations in our test suites are exported.This approach fixes an issue with Fast Refresh where some of the unexported components were being fully remounted instead of seamlessly updated. This behavior is tied to the Metro bundler's specification regarding module boundaries and state preservation. By ensuring all top-level components are explicitly exported, Metro can properly track them, which fixes the remounting issue and allows Fast Refresh to work as intended.
Changes
Before & after - visual documentation
Before
without.exports.mov
After
with.exports.mov
Test plan
Make sure that updating components of single-feature and component-integration tests triggers a correct Fast Refresh.
Checklist