NewYour coding agent can read the release notes before it upgrades.Set up the MCP server →
npm · #4278 most downloaded on npm
Error-tolerant ECMAScript parser
Last release 1 years ago
01 Jul 2025
Release timing varies
gaps range from 3 weeks to 1.8 years
Nearly every release is documented
notes for 15 of 15 stable releases
Nothing withdrawn
no release was ever pulled
8 years old
15 releases · first in 2018
Use the proper version of acorn as a dependency.
Use the proper version of acorn as a dependency.
Handle tokenizer exceptions raised by invalid numeric separators.
Handle tokenizer exceptions raised by invalid numeric separators.
Support ES2025 import attributes.
Support ES2025 import attributes.
One column per quarter.
Fix an issue where a slash after a call to a propery named the same as some keywords would be tokenized as a regular expression.
Fix an issue where a slash after a call to a propery named the same as some keywords would be tokenized as a regular expression.
Fix a bug where the parser would raise an error when an invalid escape was included in an identifier after a keyword.
Use a set of new, much more precise, TypeScript types.
Support class private fields with the in operator.
Support quoted export names.
Support class private fields with the in operator.
Fix a bug that caused semicolons after export * statements to be parsed as empty statements.
Depend on the proper version of acorn.
Depend on the proper version of acorn.
Add support for ES2022 class static blocks.
Add support for ES2022 class static blocks.
Add support for ES2022 class fields and private methods.
Add support for ES2022 class fields and private methods.
Adjust package.json to work with Node 12.16.0 and 13.0-13.6.
Adjust package.json to work with Node 12.16.0 and 13.0-13.6.
Allow for await at the top level.
Allow for await at the top level.
The package can now be loaded directly as an ECMAScript module in node 13+.
The package can now be loaded directly as an ECMAScript module in node 13+.
The ecmaVersion option is now required. For the moment, omitting it will still work with a warning, but that will change in a future release.
Fix various issues in regexp validation.
Fix various issues in regexp validation.
Add support for import.meta.
Add support for optional chaining (?.) and nullish coalescing (??).
Support export * as ns from "source".
Changes the node format for dynamic imports to use the ImportExpression node type, as defined in ESTree.
Changes the node format for dynamic imports to use the ImportExpression node type, as defined in ESTree.
### New features Support bigint syntax. Support dynamic import.
Support bigint syntax.
Support dynamic import.
This module has been moved into its own package, acorn-loose.
This module has been moved into its own package, acorn-loose.
Plugins work differently, and will have to be rewritten to work with this version.
The parse_dammit function is now simply called parse.
Your coding agent can read these notes before it upgrades. Set up the MCP server →