eval.js

const {workerData: code, parentPort} = require('worker_threads');

async function done(error, result) {
    parentPort.postMessage({error: error, result: result, logged: console._items});
}

/* most extra functions could be possibly unsafe*/
const whitey = {
    Array: 1,
    Boolean: 1,
    Date: 1,
    Error: 1,
    EvalError: 1,
    Function: 1,
    Infinity: 1,
    JSON: 1,
    Map: 1,
    Math: 1,
    NaN: 1,
    Number: 1,
    Object: 1,
    Promise: 1,
    Proxy: 1,
    RangeError: 1,
    ReferenceError: 1,
    RegExp: 1,
    Set: 1,
    String: 1,
    SyntaxError: 1,
    TypeError: 1,
    URIError: 1,
    WeakMap: 1,
    WeakSet: 1,
    atob: 1,
    btoa: 1,
    console: 1,
    decodeURI: 1,
    decodeURIComponent: 1,
    encodeURI: 1,
    encodeURIComponent: 1,
    eval: 1,
    /* our own function
    exec: 1,
    global: 1,
    isFinite: 1,
    isNaN: 1,
    onmessage: 1,
    parseFloat: 1,
    parseInt: 1,
    postMessage: 1,
    self: 1,
    undefined: 1,
    whitey: 1,*/
    /* typedarrays and shit */
    ArrayBuffer: 1,
    Blob: 1,
    Float32Array: 1,
    Float64Array: 1,
    Int8Array: 1,
    Int16Array: 1,
    Int32Array: 1,
    Uint8Array: 1,
    Uint16Array: 1,
    Uint32Array: 1,
    Uint8ClampedArray: 1,
};

function clearObj(obj, prop) {
    try {
        Object.defineProperty(obj, prop, {
            get: function () {
                /* TEE HEE */
                throw new ReferenceError(prop + ' is not defined');
            },
            configurable: false,
            enumerable: false
        });
    } catch (e) {
        delete obj[prop];

        if (obj[prop] !== undefined) {
            obj[prop] = null;
        }
    }
}

[global, Object.getPrototypeOf(global)].forEach(function (obj) {
    Object.getOwnPropertyNames(obj).forEach(function (prop) {
        if (whitey.hasOwnProperty(prop) || prop === "hasOwnProperty") {
            return;
        }
        clearObj(obj, prop);
    });
});

/*
Object.defineProperty(Array.prototype, 'join', {
    writable: false,
    configurable: false,
    enumrable: false,

    value: (function (old) {
        return function (arg) {
            if (this.length > 500 || (arg && arg.length) > 500) {
                throw 'Exception: too many items';
            }

            return old.apply(this, arguments);
        };
    }(Array.prototype.join))
});
*/


const console = {
    _items: [],
    log: function () {
        console._items.push.apply(console._items, Array.from(arguments).map(e => JSON.stringify(e)));
    }
};
console.error = console.info = console.debug = console.log;

function exec(code) {
    clearObj(module, require);
    return eval(`undefined;\n${code}`);
}

try {
    done(false, exec(code));
} catch (e) {
    done(false, e.toString());
}