cherow

Cherow

WORK IN PROGRESS

Cherow is a very fast and unbeatable, standard-compliant ECMAScript parser written in ECMAScript.

It's close to 100% ECMAScript spec compatible.

Note! The source exist in the "dev" branch

Features

• Full support for ECMAScript 2017 (ECMA-262 8th Edition)
• 100 % TC262 Compatible
• JSX
• TypeScript (in progress)
• Optional tracking of syntax node location (index-based and line-column)
• 4300 unit tests with full code coverage

ESNext features

Stage 3 features support. This need to be enabled with the next option

• Dynamic Import
• Async generators
• Async Await
• Object spread
• BigInt
• Optional catch binding
• Regular Expression's new DotAll flag

Options

• next - Enables ECMAScript Next support and let you use proposals at stage 3 or higher such as Dynamic Import.
• directives - Enables support for directive nodes
• raw - Enables the raw property on literal nodes (Esprima and Acorn feature)
• onComment - Enables option to collect comments. Optional; Either array or function. Works like Acorn onComment.
• tokenize - If enabled each found token will be returned as either an function or an array (work in progres)
• ranges - Enables the start and characters offsets on the AST node.
• locations - Enables location tracking. (4 min fix, but on hold for now)
• jsx - Enables JSX
• ts - Enables TypeScript (coming very soon)

Benchmarks

To be written

Contribution

You are welcome to contribute. As a golden rule - always run benchmarks to verify that you haven't created any bottlenecks or did something that you shouldn't.

Terms of contribution:

• Think twice before you try to implement anything
• Minimum 1.5 mill ops / sec for light weight cases, and 800k - 1 mill ops / sec for "heavy" cases
• Avoid duplicating the source code
• Create tests that cover what you have implemented