ES6 Awesomeness

rot32.js

const _DICTIONARY = new Array(96).fill('').map((a,v) => String.fromCharCode(32 + v));
const _encode_rot32 = function(string) {
	return Array.prototype.map.call(string, val => _DICTIONARY[(32 + _DICTIONARY.indexOf(val)) % _DICTIONARY.length]).join('');
};

const _decode_rot32 = function(string) {
	return Array.prototype.map.call(string, val => _DICTIONARY[(_DICTIONARY.indexOf(val) - 32 + _DICTIONARY.length) % _DICTIONARY.length]).join('');
};


// Usage

_encode_rot32('hello world');

let secret = _encode_rot32('hello world');
let plain  = _decode_rot32(secret);

console.log(secret);
console.log(plain);

awesome!

[].map.call would be even shorter!