Simple hexdump in Javascript

hexdump.js

function hexdump(buffer, blockSize) {
	//determine the type of variable "buffer", and convert this to "string".
	if(typeof buffer === 'string'){
		//console.log("buffer is string");
		//do nothing
	}else if(buffer instanceof ArrayBuffer && buffer.byteLength !== undefined){
		//console.log("buffer is ArrayBuffer");
		buffer = String.fromCharCode.apply(String, [].slice.call(new Uint8Array(buffer)));
	}else if(Array.isArray(buffer)){
		//console.log("buffer is Array");
		buffer = String.fromCharCode.apply(String, buffer);
	}else if (buffer.constructor === Uint8Array) {
		//console.log("buffer is Uint8Array");
		buffer = String.fromCharCode.apply(String, [].slice.call(buffer));
	}else{
		//console.log("Error: buffer is unknown...");
		return false;
	}
	
	
	blockSize = blockSize || 16;
	var lines = [];
	var hex = "0123456789ABCDEF";
	lines.push('var byte_array = [', "//hex, //ASCII, //start offset. (block-size = "+blockSize+" bytes/per line)"); //now this like variable, and can be used in script.
	for (var b = 0; b < buffer.length; b += blockSize) {
		var block = buffer.slice(b, Math.min(b + blockSize, buffer.length));
		var addr = ("0000" + b.toString(16)).slice(-4);
		var codes = block.split('').map(function (ch) {
			var code = ch.charCodeAt(0);
			return ' ' + '"0x'+hex[(0xF0 & code) >> 4] + hex[0x0F & code]+'",';
		}).join("");
		codes += "	".repeat(blockSize - block.length);
		var chars = block.replace(/[\x00-\x1F\x20]/g, '.');
		chars +=  " ".repeat(blockSize - block.length);
//		lines.push(addr + " " + codes + "  " + chars);				//old code
		lines.push(codes + "  //" + chars +"	0x"+addr);			//new code
	}
	lines.push('];');
	return lines.join("\n");
}

function decode(base64) { //decode base64
	base64 = base64 || '';
	return atob(base64.replace(/_/g, '/').replace(/-/g, '+'));
}

function d(base64_encoded_string) {//use base64 encoded string, on input
	console.log(hexdump(decode(base64_encoded_string)));
}

function run_tests(){
	//tests:
	var buffer = 'very very long string; very very long string; very very long string;';		//long string	- working
	console.log("buffer is string");
	console.log( hexdump( buffer , 16 ) ) ;

	var buffer = new Uint8Array([1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20]).buffer;	//arrayBuffer	- working
	console.log("buffer is ArrayBuffer");
	console.log( hexdump( buffer , 16 ) ) ;

	var buffer = [41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60];			//bytearray	- working
	console.log("buffer is Array");
	console.log( hexdump( buffer , 8 ) ) ;

	var buffer = new Uint8Array([21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40]);	//Uint8Array	- working
	console.log("buffer is Uint8Array");
	console.log( hexdump( buffer , 4 ) ) ;

	console.log("base64-encoded string:");
	d('dmVyeSB2ZXJ5IGxvbmcgc3RyaW5nOyB2ZXJ5IHZlcnkgbG9uZyBzdHJpbmc7IHZlcnkgdmVyeSBsb25nIHN0cmluZzsg');	//string base64 - working

	console.log("base64-encoded string - from string");
	d(window.btoa('very very long string; very very long string; very very long string;'));	//convert string to base64 - working
	
	//try to get string, after some time.
	setTimeout(
		function(){
			var buffer = 'blah-blah-blah-blah-very-very-long-blah-blah...'; 
			eval(
				hexdump( buffer , 16 )+		//this function return the variable "var byte_array", as text, so we can define this, using eval.
				'console.log("\\n\\nbuffer = ", buffer,\n\
					"\\n\\nhexdump( buffer , 16 ):\\n"+hexdump( buffer , 16 ),\n\
					"\\n\\nbytearray = ", byte_array,\n\
					"\\n\\nstring from bytearray = ", byte_array.map(x => String.fromCharCode(x)).join("")\n\
				);'  //this is a text for second command, to get string from already defined "var byte_array".
			)//all this two commands are a string, and running as javascript code, using eval.
		}
		,
		1000	//run this string, after 1000 milliseconds.
	);
}

run_tests(); //run tests

Now, this hex-dump, is an array.