https://github.com/ben-sb/jisu

JavaScript Parser
https://github.com/ben-sb/jisu

javascript parser tokeniser

Last synced: about 2 months ago
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JavaScript Parser

• Host: GitHub
• URL: https://github.com/ben-sb/jisu
• Owner: ben-sb
• License: apache-2.0
• Created: 2022-06-28T17:21:04.000Z (over 2 years ago)
• Default Branch: master
• Last Pushed: 2024-09-16T15:47:44.000Z (5 months ago)
• Last Synced: 2024-09-16T19:05:15.258Z (5 months ago)
• Topics: javascript, parser, tokeniser
• Language: TypeScript
• Homepage: https://ben-sb.github.io/jisu/
• Size: 458 KB
• Stars: 9
• Watchers: 1
• Forks: 0
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# JISU

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

## About

JISU is *mostly* a recursive descent parser. It uses the bottom-up [precedence climbing method](https://en.wikipedia.org/wiki/Operator-precedence_parser) to parse binary and logical expressions.

## Specs

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.

```typescript

interface ParserOptions {

    emitLogs?: boolean;

    omitLocations?: boolean;

}

```

I'm a big fan of [Babel](https://github.com/babel/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*.

## Tests

Unit tests can be run via ```npm test```


Currently there are very few tests but I plan to add more.

## To Do

* 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

## To Fix

* 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