IE11-compatible version of Brian Beck's eval-in-context

eval_in_context.js

// https://twitter.com/ua6oxa/status/1170457046153650176
"use strict";

function evalInContext(env, code) {
  const
    s = JSON.stringify,
    locals = Object.keys(env),
    keys = locals.map(function(k){return s(k)}),
    values = locals.map(function(k){return env[k]}),
    body = s("return eval(" + code + ")")
  return eval("new Function("+keys+","+body+")").apply(this, values)
}

console.assert(3==evalInContext({a: 1, b: 2}, "a + b"))
try {console.log(a)}
catch(e) {console.log("Success! No pollution of namespace")}