reflect.getprototypeof 
An ES2015 mostly-spec-compliant Reflect.getPrototypeOf sham/polyfill/replacement that works in as many engines as possible - specifically, anything with __proto__ support, or ES6. Built-in types will also work correctly in older engines.
This package implements the es-shim API interface. It works in an ES3-supported environment and complies with the spec.
Example
var getPrototypeOf = require('reflect.getprototypeof');
var assert = require('assert');
assert.throws(() => getPrototypeOf(true));
assert.throws(() => getPrototypeOf(42));
assert.throws(() => getPrototypeOf(''));
assert.equal(getPrototypeOf(/a/g), RegExp.prototype);
assert.equal(getPrototypeOf(new Date()), Date.prototype);
assert.equal(getPrototypeOf(function () {}), Function.prototype);
assert.equal(getPrototypeOf([]), Array.prototype);
assert.equal(getPrototypeOf({}), Object.prototype);
var getPrototypeOf = require('reflect.getprototypeof');
var assert = require('assert');
/* when Reflect or Reflect.getPrototypeOf is not present */
if (typeof Reflect === 'object') { delete Reflect.getPrototypeOf; }
delete globalThis.Reflect;
var shimmed = getPrototypeOf.shim();
assert.equal(shimmed, getPrototypeOf.getPolyfill());
assert.throws(() => Reflect.getPrototypeOf(true));
assert.throws(() => Reflect.getPrototypeOf(42));
assert.throws(() => Reflect.getPrototypeOf(''));
assert.equal(Reflect.getPrototypeOf(/a/g), RegExp.prototype);
assert.equal(Reflect.getPrototypeOf(new Date()), Date.prototype);
assert.equal(Reflect.getPrototypeOf(function () {}), Function.prototype);
assert.equal(Reflect.getPrototypeOf([]), Array.prototype);
assert.equal(Reflect.getPrototypeOf({}), Object.prototype);
var getPrototypeOf = require('reflect.getprototypeof');
var assert = require('assert');
/* when Reflect.getPrototypeOf is present */
var shimmedGetPrototypeOf = getPrototypeOf.shim();
assert.equal(shimmedGetPrototypeOf, Reflect.getPrototypeOf);
assert.equal(Reflect.getPrototypeOf([]), Array.prototype);
Tests
Simply clone the repo, npm install, and run npm test