vm

require('vm')

run a string of code in the sandbox

The vm package takes an argument of code and one of context - you don't get access to stdin or stdout, but you can pass in custom methods: like a custom method for console.log. Through this mechanism you can write back values out of the sandbox maintaining semantics. It's pretty darn useful.

const assert = require('assert')
const vm = require('vm')

const sandbox = {
  console: {
    log: (msg) => assert.equal(msg, 'hey there')
  }
}

const okCode = `
  console.log('hey there')
`

const ohnoCode = `
  console.log('hey where?')
`

vm.runInNewContext(okCode, sandbox)
// => :D

vm.runInNewContext(ohnoCode, sandbox)
// => :C

See Also

• https://nodejs.org/api/vm.html