JavaScript hexdump

hexdump.js

function hexdump(buffer, bytesPerRow) {
	bytesPerRow = bytesPerRow || 16;
	const hexDigits = "01234567890abcdef";
	var str = "";

	for (var addr = 0; addr < buffer.length; addr += bytesPerRow) {
		var rowStr = ("0000" + addr.toString(16)).slice(-4) + ":";
		for (var i = addr; i < addr + bytesPerRow; i++) {
			if (i < buffer.length) {
				rowStr += " " + hexDigits[(0xf0 & buffer[i]) >> 4] + hexDigits[0x0f & buffer[i]];
			} else {
				rowStr += "   ";
			}
		}
		rowStr += "  ";
		for (var i = addr; i < addr + bytesPerRow; i++) {
			if (i < buffer.length) {
				if (buffer[i] > 32 && buffer[i] < 127) {
					rowStr += String.fromCharCode(buffer[i]);
				} else {
					rowStr += ".";
				}
			}
		}
		str += rowStr + "\n";
	}
	return str;
}