Creating dynamically named getters and setters on an object

dynamically-named getters and setters.js

/**
 * And this is the winning version thanks to @gf3. Using Object.keys().forEach()
 * is faster than for..in as benchmarked by @creationix here:
 * https://gist.github.com/75d0278890e6c5833add
 * According to @jdalton, this is because for..in looks up the prototype chain
 * while Object.keys looks at own keys.
**/

var obj1 = {
  a: "a",
  b: "b",
  c: "c"
};

var obj2 = {};

Object.keys( obj1 ).forEach( function( key ) {
  obj2.__defineGetter__(key, function() {
    return obj1[key];
  });
});

console.log(obj2.a, obj2.b, obj2.c);

// EXPECTED:
// --> a
// --> b
// --> c