npm / @babel/standalone
@babel/standalone
What changed in @babel/standalone 8, from its official release notes, upgrade guides and advisories. Sources checked 2026-10-28.
6 breaking1 performance24 fixes and other
See which of these apply to your code, ranked, in your agent:
npx @unstale/cli init@babel/standalone 831 changes
Breaking changes 6
The parser now disallows named specifiers after * as ns, enforcing spec-compliant syntax.
The parser now disallows const x followed by a linebreak and of, enforcing spec-compliant syntax.
The parser now disallows arrow functions as a new callee and as an await operand.
The parser now disallows call expressions as arrow function parameters in sloppy mode.
The parser now disallows eval and arguments as class names.
Identifier definitions now use Unicode 18, changing which identifiers the parser accepts.
Performance 1
Spreading literals no longer requires arrayLikeToArray.
Fixes and other changes 24
_arrayWithHoles no longer bypasses a custom Symbol.iterator on array-backed Proxies.
The parser now allows arguments as a label in a class.
The parser now handles automatic semicolon insertion between a property initializer and escaped in.
Function IDs in labeled function declarations are now registered.
The parser now skips HTML-like comments during character lookahead.
The parser now allows automatic semicolon insertion after export default from without exportDefaultFrom.
With createParenthesizedExpressions enabled, the parser now rejects delete (x).
The parser now reports expression errors in object literals used as a member base.
Non-deferred imports now receive phase: null when deferredImportEvaluation is enabled.
The parser now handles automatic semicolon insertion between an arrow body and a /= regex.
The transform now wraps an enclosing loop when a nested for-head closure captures its bindings.
Decorators of TSParameterProperty are now visited during transformation.
The eslint-parser AST definition for
AccessorPropertywas fixed.The helper now forwards
.throw()to.return()correctly.The parser now allows
awaitas a function expression name inside an async arrow.The function now allows a callback as its second argument.
Closures in for-loop initializers now capture the correct binding.
Evaluation now handles TypeScript expression wrappers.
Destructured bindings are no longer evaluated.
The helper now guards
@@toPrimitiveusage.The transform now skips for-await loops, avoiding incorrect handling of asynchronous iteration.
The expression now returns false for static private fields before initialization.
Parsing of arrow function parameters inside ternaries with Flow is fixed.
The error message for invalid binary literal 0b19 is polished.