README.md

jsscript

A JavaScript Runtime implement in JavaScript.

Inspired by QuickJS.

Goal

• Provide a easy way to learning JavaScript engine. No needs to learn C.
• Only support strict mode and modern JavaScript feature.
  • Such as let, const, async, await, arrow function, class, etc.
  • Not implement with, eval, var, label etc.
• Please do not using this project for your production without any tested.
• Flexable, you can only use the part of JavaScript.
• Some prototype function of Builtin Object depends on the host environmnet.
  • For example, if you want to use Array.prototype.at in vm, you need make sure it can been used in host vm. Or you need to load ployfill.

How to use

CLI

# instal as global
npm install @xgheaven/jsscript -g

It's like Node.js cli without special module.

jsscript run your-file.js

API

# install
npm install @xgheaven/jsscript

import { Runtime, Features, parseScript, parseBytecode, toHostValue } from 'jsscript'

const runtime = new Runtime({
  features: [
    // inject builtin features
    new Features.ECMA262Feature(), // inject All ECMA262 Spec object, like `Promise`/`RegExp`/...
    // you can write your self feature
  ],
})
const context = runtime.newContext()

const script = `<your-script>`;

// parse it to function object
const fn = parseScript(context, script)
// or compile it bytecode then parse it
const bc = compileToBytecode(script)
const fn = parseBytecode(context, bc)

// run it
const ret = context.run(fn)

// convert js value of vm to host vm
console.log(toHostValue(ret))

Error Handle

TODO

Define Feature

TODO

Benchmark(TODO)

The performance is not the core of jsscript. But It's still important for using. Using v8-7 version benchmark test. (It's so old, only support es5. I will find more newer test cases in the future to replace it)

	jsscript	sablejs	eval5
Language	TypeScript	JavaScript	TypeScript
Support Version	ES6(target)	ES5	ES5
Version	see package.json	1.1.0	1.4.7
crypto Score	-	-	-
deltablue Score	-	-	-
earley-boyer Score	-	-	-
navier-stokes Score	-	-	-
raytrace Score	-	-	-
regexp Score	-	-	-
richards Score	-	-	-
splay Score	-	-	-
Total Score	-	-	-

More

I want to use jsscript as package name. But it too similar to the package js-script which published 10+ years ago. I have to add the personal scope in the package name.

Same package

• engine262