Skip to content
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

Jump to bottom

Add support for static evaluation of ?? operator #14837

Merged
merged 1 commit into from Aug 9, 2022
Merged

Add support for static evaluation of ?? operator #14837

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.
Jump to
Jump to file
Failed to load files.
Diff view
Diff view
5 changes: 5 additions & 0 deletions packages/babel-traverse/src/path/evaluation.ts
View file
Open in desktop
Expand Up @@ -309,6 +309,11 @@ function _evaluate(path: NodePath, state: State): any {
if (!state.confident) return;

return left && right;
case "??":
state.confident = leftConfident && (left != null || rightConfident);
if (!state.confident) return;

return left ?? right;
}
}

Expand Down
8 changes: 8 additions & 0 deletions packages/babel-traverse/test/evaluation.js
View file
Open in desktop
Expand Up @@ -68,6 +68,14 @@ describe("evaluation", function () {
expect(getPath("0 && x === 'y'").get("body")[0].evaluate().value).toBe(0);
});

it("should handle ??", function () {
expect(getPath("null ?? 42").get("body")[0].evaluate().value).toBe(42);
expect(getPath("void 0 ?? 42").get("body")[0].evaluate().value).toBe(42);
expect(getPath("0 ?? 42").get("body")[0].evaluate().value).toBe(0);
expect(getPath("x ?? 42").get("body")[0].evaluate().confident).toBe(false);
expect(getPath("42 ?? x === 'y'").get("body")[0].evaluate().value).toBe(42);
});

it("should work with repeated, indeterminate identifiers", function () {
expect(
getPath("var num = foo(); (num > 0 && num < 100);")
Expand Down