Skip to content

Guard private syntax preservation by transform profile #58253

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
OskarEichler wants to merge 1 commit into
base: main
Choose a base branch
from
+26 −4
Open

Guard private syntax preservation by transform profile #58253

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
19 changes: 19 additions & 0 deletions packages/react-native-babel-preset/src/__tests__/transform-snapshot-test.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -444,6 +444,25 @@ describe('react-native-babel-preset transform snapshots', () => {
expect(result).toContain('_classPrivateFieldLooseKey');
});

it('transforms private class fields when the profile lowers classes', () => {
const code = `
class Counter {
#count = 0;
#privateMethod() { return this.#count; }
}
`;
const result = transformCode(code, {
dev: false,
unstable_transformProfile: 'hermes-legacy',
customTransformOptions: {
unstable_preserveClassPrivate: true,
},
});
expect(result).not.toContain('#count');
expect(result).not.toContain('#privateMethod');
expect(result).toContain('_classPrivateFieldLooseKey');
});

it('preserves async/await with unstable_preserveAsync', () => {
const code = `
async function fetchData() {
Expand Down
11 changes: 7 additions & 4 deletions packages/react-native-babel-preset/src/configs/main.js
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -94,10 +94,13 @@ const getPreset = (src, options, babel) => {
// Preserve class syntax and related features for Hermes V1 profiles.
const preserveClasses = isHermesProfile;

// Preserve private class fields and methods if the experiment is enabled.
const preserveClassPrivate = TRUE_VALS.has(
options?.customTransformOptions?.unstable_preserveClassPrivate,
);
// Private fields can only be preserved when the surrounding class syntax is
// also preserved. Babel's class transform requires the private transforms.
const preserveClassPrivate =
preserveClasses &&
TRUE_VALS.has(
options?.customTransformOptions?.unstable_preserveClassPrivate,
);

// Preserve async/await syntax if the experiment is enabled.
const preserveAsync = TRUE_VALS.has(
Expand Down
Loading