IEEE 754 Converter : Any Bit Float to Binary and Back

floatingbin.js

/*
	Floating Bin JS Script
	Nizar Mahmoud https://nizarmah.me/

	IEEE 754 Converter
		Float to Binary
		Binary to Float
	Bits : 16, 32, 64, 128, 256

	Use freely, just would appreciate
	keeping this comment on top to
	show me off to other people

	Thanks to https://twitter.com/MrNoahz
	for being a thorough tester of this

	And thanks to stackoverflow and the 
	kind dudes phimuemue and Rudy
	https://stackoverflow.com/questions/6910115/
	how-to-represent-float-number-in-memory-in-c#6910674
*/

function _convert(string, base) {
	string = string.toString().trim().split(".");
    base = +base || 2;
    
    return (parseInt(string[0].replace("-", ""), base) + (string[1] || "").split("").reduceRight((sum, bit) => (sum + parseInt(bit, base)) / base, 0)) * (+(string[0][0] !== "-") || -1);
}

function _sniffer(bit) {
	var expSize;

	switch (bit) {
		case 16:
			expSize = 5;
			break;
		case 32:
			expSize = 8;
			break;
		case 64:
			expSize = 11;
			break;
		case 128:
			expSize = 15;
			break;
		case 256:
			expSize = 19;
			break;
		default: return false;
	}

	return { exp: expSize, flt: bit - (expSize + 1), bias: ((Math.pow(2, (expSize - 1))) - 1) };
}

function flt2bin(flt, bit) {
	var bin = "";
	var binList;
	bit = bit || 32;

	binSizes = _sniffer(bit);
		if (!binSizes)
			return false;

	if (flt == Infinity || flt == -Infinity || flt.toString() == "NaN") {
		if (flt == -Infinity)
			bin += "1";
		else bin += "0";

		var pow = "";
		while (pow.length < binSizes.exp)
			pow += "1";
		bin += pow;

		if (flt == NaN)
			bin += "1";

		while (bin.length < bit)
			bin += "0";

		return bin;
	} 

	if (flt >= 0)
		bin += "0";
	else bin += "1";

	flt = Math.abs(flt);

	if (!flt.toString().indexOf(".")) {
		binList = [ (flt).toString(2) ];
	} else binList = (flt).toString(2).split(".");

	var exp;
	if (binList[0] != 0) {
		exp = binList[0].length - 1;
	} else {
		if (binList.length > 1) {
			if (binList[1].indexOf("1") > -1) {
				exp = -1 * (binList[1].indexOf("1") + 1);
			} else exp = -binSizes.bias;
		} else exp = -binSizes.bias;
	}

	var expBias = (exp + binSizes.bias).toString(2).split("");
	while (expBias.length < binSizes.exp)
		expBias.unshift("0");
	bin += expBias.toString().replace(/,/g, '');

	if (exp >= 0) {
		bin += binList[0].substr(1, binList[0].length);

		if (binList.length > 1)
			bin += binList[1];
	} else {
		if (binList.length > 1)
			bin += binList[1].substr(Math.abs(exp), binList[1].length);
		else bin += "0";
	}

	if (bin.length >= bit) {
		bin = bin.substr(0, bit);
	} else {
		while (bin.length < bit)
			bin += "0";
	}

	return bin;
}

function bin2flt(bin, bit) {
	var binList = bin.split("");
	bit = bit || 32;

	binSizes = _sniffer(bit);
		if (!binSizes)
			return false;

	var s, e, m;
	for (var i = 0; i < bit; i++) {
		if (i < 1) {
			s = binList[i];
		} else if (i < (binSizes.exp + 1)) {
			if (i == 1) e = binList[i];
			else e += binList[i];
		} else if (i < binList.length) {
			if (i == (binList.length - binSizes.flt)) m = binList[i];
			else m += binList[i];
		}
	}

	if (e.indexOf("0") < 0) {
		if (m.indexOf("1") < 0) {
			if (s == 1)
				return -Infinity;
			else return Infinity;
		} else return NaN;
	}

	if (e.indexOf("1") < 0)
		return 0;

	if (s == "1") s = "-1";
	else s = "1";

	e = _convert(e, 2);
	e = e - binSizes.bias;

	m = "1." + m;
	m = _convert(m, 2);

	return (s * m * Math.pow(2, e));
}