var input_ascii = [72, 101, 108, 108, 111, 44, 32, 119, 111, 114, 108, 100, 33];

var output_str = [];
for (var i = 0; i < input_ascii.length; i++) {
	output_str.push(String.fromCharCode(input_ascii[i]));
}

// "Hello, world!"
console.log(output_str.join(''));

var output_ascii = [];
var output_hex = [];
for (var i = 0; i < output_str.length; i++) {
	// Char to ASCII code
	output_ascii.push(output_str[i].charCodeAt(0));
  
	// Char to hexadecimal number
	output_hex.push(output_str[i].charCodeAt(0).toString(16));
}

// 72,101,108,108,111,44,32,119,111,114,108,100,33
console.log(output_ascii);

// 48,65,6c,6c,6f,2c,20,77,6f,72,6c,64,21
console.log(output_hex);