20X performance improvement on Nodejs, just by caching process.env with a single line: process.env = JSON.parse(JSON.stringify(process.env));

benchmark_env.js

// ****************************
//* ********* OUTPUT **********
//* **** 20X Improvement ******
//* ******** Tested on ********
//* ****** Node v10.14.2 ******
// ****************************
// Start testing : Original
// Original, #0: 1299.590ms
// Original, #1: 1268.201ms
// Original, #2: 1261.733ms
// Original, #3: 1262.137ms
// Original, #4: 1277.845ms
// Original total: 6372.165ms
// process.env.OS:  Windows_NT
//
// ****************************
// Caching: 0.312ms
// ****************************
//
// Start testing : Cached
// Cached, #0: 43.721ms
// Cached, #1: 44.087ms
// Cached, #2: 44.561ms
// Cached, #3: 43.703ms
// Cached, #4: 43.713ms
// Cached total: 219.999ms
// process.env.OS:  Windows_NT
// ****************************

// benchmark process.env
function benchmark(label, iterations = 5, accessTimes = 10 * 1000 * 1000) {
  let os; let i; let j;
  console.log(`Start testing : ${label}`);

  // total timer
  console.time(`${label} total`);

  // run 5 iterations, each with 10m env access
  for (i = 0; i < iterations; i += 1) {
    // iteration timer
    console.time(`${label}, #${i}`);
    for (j = 0; j < accessTimes; j += 1) {
      os = process.env.OS;
    }
    console.timeEnd(`${label}, #${i}`);
  }
  console.timeEnd(`${label} total`);

  // just make sure we are accessing a valid value
  console.log('process.env.OS: ', os);
}

// benchmark the original process.env
benchmark('Original');

console.log('\n****************************');
console.time('Caching'); // how long the caching takes

// cache process.env, to override native getters
process.env = JSON.parse(JSON.stringify(process.env));

console.timeEnd('Caching');
console.log('****************************\n');

// benchmark the cached version
benchmark('Cached');

Hello What Is This For

Hello @DevPreston1,

This optimization can be used for NodeJs applications that use process.env heavily,
Such as checking the env for every client request,

process.env is a live object that make use of underlying c++ getters to resolve the env var you are looking for, which is quite costly:
https://github.com/nodejs/node-v0.x-archive/blob/b922b5e/src/node.cc#L2326-L2335

So with simple caching we can improve the performance of such application 20X (in terms of accessing the env) using:
process.env = JSON.parse(JSON.stringify(process.env));

New versions of node seem to optimize for this, but it wouldn't hurt using with older Node versions:
nodejs/node#3104 (comment)

Its not quite known, this is the only result that i can find that use this approach:
nodejs/node#3104 (comment)
facebook/react#812 (comment)

Best Regards,
Ahmed