BlackDice/b3-chief

import { init } from 'stampit'
import debug from 'debug'

const Compiler = init(initializeCompiler)

const log = debug('chief:compiler')

const defaultTranspiler = (code) => code

function initializeCompiler({ transpiler = defaultTranspiler, onError = log }) {
    this.compiler = getVMCompiler(transpiler, onError) || getEvalCompiler(transpiler, onError)
}

function getVMCompiler(transpiler, onError) {
    const vm = getVM()
    if (vm === null) {
        return null
    }

    const sandbox = {}
    vm.createContext(sandbox)

    function compile(code) {
        try {
            return vm.runInContext(transpiler(code), sandbox)
        } catch (err) {
            onError(err)
            return null
        }
    }

    return compile
}

function getVM() {
    try {
        return require('vm') // eslint-disable-line
    } catch (err) {
        return null
    }
}

function getEvalCompiler(transpiler, onError) {
    const evaluate = eval // eslint-disable-line no-eval

    function compile(code) {
        try {
            return evaluate(transpiler(code))
        } catch (err) {
            onError(err)
            return null
        }
    }

    return compile
}

export default Compiler