A work in progress JavaScript tokeniser and parser. Currently only supports a subset of the JavaScript language and is not ECMAScript compliant.
Install via npm install jisu
An online demo is available at https://ben-sb.github.io/jisu
JISU is mostly a recursive descent parser. It uses the bottom-up precedence climbing method to parse binary and logical expressions.
The repo has two exports:
- parse - Parses a full program
- parseExpression - Parses a single expression
Both take the input as a string and optionally a set of parser options.
interface ParserOptions {
emitLogs?: boolean;
omitLocations?: boolean;
}I'm a big fan of Babel and as a result the format of the AST JISU produces is extremely similar to Babel's. As a result @babel/generator can be used on the AST (as seen in src/demo.ts). I also took inspiration from the @babel/types package and implemented a similar system in src/parser/ast.
Unit tests can be run via npm test
Currently there are very few tests but I plan to add more.
- Rewrite object member parsing
- Allow semi-keywords (e.g. await, async, of) to be treated as identifiers
- Support numbers expressed in hexadecimal, octal and scientific notation
- Support regular expressions
- Probably a lot more
- Object patterns are treated as normal object expressions even when not used as a pattern
- Spread elements are allowed in sequence expressions
- Spread elements are allowed on their own in parenthesised expressions