yzhanJSInterpreter

yzhanJSInterpreter

A JavaScript Interpreter Using JS itself, implement eval
JavaScript 解释器，包含词法分析、语法解析和执行。实现 eval

Demo

You could change JavaScript Code and view the result in realtime.
Online Demo

Setup

Node.js

npm i yzhanjsinterpreter
import yzhanJSInterpreter from 'yzhanjsinterpreter'

Browser

<script src="https://cdn.jsdelivr.net/npm/yzhanjsinterpreter@latest/docs/yzhanjsinterpreter.min.js"></script>

Usage

Declaration Code

const code = `let a = 1;
let b = 1;
a <<= b++;
for (let i = 0; i < 10; i++) {
  if (i % 2 === 0) continue;
  if ((i | 2) == '11') break;
  a++;
}
undefined && 1 ?? (0 || a + b);`

Eval · Evaluate

eval is a reserved keyword, so use evaluate instead

const evalResult = yzhanJSInterpreter.evaluate(code)

evaluate runs followed 3 steps:

1. Lexical Analyzer

const lexResult = yzhanJSInterpreter.lex(code)

2. Syntax Parser

const parseResults = yzhanJSInterpreter.parse(lexResult)

3. Executor

const executeResult = yzhanJSInterpreter.execute(parseResults[0])
const evalResult = executeResult

Development

Unit Testing

npm test

Build

npm run build

Preview

npm run dev

Todo

1. Travese AST, using child to replace the parent when there is only one parent Node.
2. Treeshaking: earse unseded declarations.