hex encoding/decoding for the browser and node.js
var hex = require("hex_encoding");
hexEncoding.stringToBytes(
"7468697320697320612074657374"
) === [116, 104, 105, 115, 32, 105, 115, 32, 97, 32, 116, 101, 115, 116];
hexEncoding.bytesToString(
[116, 104, 105, 115, 32, 105, 115, 32, 97, 32, 116, 101, 115, 116]
) === "7468697320697320612074657374";