Create a context for executing code in a sanbox using Node.js runtime Package: https://nodejs.org/docs/latest-v18.x/api/vm.html

ctx-sandbox-a-nodejs.js

// https://nodejs.org/docs/latest-v18.x/api/vm.html
const vm = require("vm");

// create an object in heap
const sandboxCtx = {};

// Contextify the sandbox.
vm.createContext(sandboxCtx); 
let code = 'var human = 2; let fish = "a big fish :)"';

// no support for let, const keywords so replace
code = code.replace(/let|const/, "var"); 

// run the code: Note: "vm" module does not gurantee safety
// see "vm2" [https://github.com/patriksimek/vm2] for more safe alternative 
// especially when getting input from user :(
vm.runInContext(code, sandboxCtx);

console.log(sandboxCtx);

ctx-sandbox-b-nodejs.js

// https://nodejs.org/docs/latest-v18.x/api/vm.html
const vm = require("vm");

// create an object in heap
// key/value gets updated in sandbox
const sandboxCtx = {fish: "a small fish"};

// Contextify the sandbox.
vm.createContext(sandboxCtx); 
let code = 'var human = 2; let fish = "a big fish :)"';

// no support for let, const keywords so replace
code = code.replace(/let|const/, "var"); 

// run the code: Note: "vm" module does not gurantee safety
// see "vm2" [https://github.com/patriksimek/vm2] for more safe alternative 
// especially when getting input from user :(
vm.runInContext(code, sandboxCtx);

console.log(sandboxCtx);
console.log(sandboxCtx.fish) // a big fish :)