Develop Reference

How to convert big number to string value in JavaScript without using any external lib?

Convert the ASCII value sentence to its equivalent string
This is for writing a similar program given above. I tried to convert the input directly to string value for the iteration.
What is happening is, assume the input value is
var num = 23511011501782351112179911801562340161171141148;
When I convert this number to string
num.toString()
I'm getting the result like this:
"2.351101150178235e+46"
There are so many similar questions asked in SOF, but I didn't see any proper answers.
Can someone help me with how to iterate each value in the input?
Thanks in advance.

If I understand you mean correctly, you can replace the code char ch = (char)num; with var ch = String.fromCharCode(num);. Like this:
var result = [];
function asciiToSentence(str, len)
{
var num = 0;
for (var i = 0; i < len; i++) {
// Append the current digit
num = num * 10 + (str[i] - '0');
// If num is within the required range
if (num >= 32 && num <= 122) {
// Convert num to char
var ch = String.fromCharCode(num);
result.push(ch)
// Reset num to 0
num = 0;
}
}
}
var str = "7110110110711510211111471101101107115";
var len = str.length;
asciiToSentence(str, len);
console.log(result.join(''));
Reference: String.fromCharCode()
Explanation:
First, inside the function asciiToSentence, we need 2 parameters str and len (str is a string while len is the length of that string).
Next, we make a temporary num to calculate the number inside the string based on this table: ASCII Printable Characters
We trying to parse one-by-one character to a number and multiply it with 10. Then, we compare it between 32 and 122 (based on the number in the table above).
If the number we have is inside the range, we parse that number to a character using String.fromCharCode function and reset the value num. Otherwise, we continue the loop and increase the value num

Elegant way to split hex string at byte 00?

I need to split a hex string at every 00 byte. I tried this:
string.split('00');
But that causes splits at 5009, for instance, which is incorrect because it is splitting a byte in half.
In other words, it turns 5009 to [5, 9], which I don't want. But I do want it to turn af0059 to [af, 59].
Is it even possible to split bytes using regex, without cutting any bytes in half?
I could use a loop to seek through the string and only divide the string at even-number indices, but I would much prefer a regex expression.

Because of the byte sizes, you need to first split the string into byte-sizes, then map and finally join.
const string = "af00b9e00f70";
const res = string.split(/([\d\w]{4})/).filter(e => e).map(e => e.replace(/00([\d\w]{2})/, "$1").replace(/([\d\w]{2})00/, "$1")).join("");
console.log(res);

Here's a somewhat "old school' approach, but it demonstrates the principal. I say "old school' because we had to do this all the time back in the days of assembler coding. 'string' contains your long string of hex pairs (bytes). Here I convert it to byte values. Change the 'string' to whatever you want, but be sure it has an even number of hex digits. Call 'translate' to demonstrate it, and format the output into an alert() (or just output to the console)
var values = []; // output array
var string = "000102030405060708090a0b0c0d0e0f1FFFFEFDFCFBFAF9F8F7F6F5F4F3F2F0";
function getHexByteValues( string) {
var hex= "0123456789ABCDEF";
var outIx=0;
for (var i =0; i <= (string.length-2); i +=2) { // skip every other
//get higher and lower nibble
var hexdig1 = string.substring(i, i+1);
var hexdig0 = string.substring(i+1, i+2);
// for simplicity, convert alpha to upper case
hexdig1 = hexdig1.toUpperCase();
hexdig0 = hexdig0.toUpperCase();
// convert hex to decimal value.
// position in lookup string == value
var dec1 = hex.indexOf(hexdig1);
var dec0 = hex.indexOf(hexdig0);
// calc "byte" value, and add to values.
values[outIx++] = dec1 * 16 + dec0;
}
}
function translate(string) {
getHexByteValues(string);
var output="";
for (var i =0; i < values.length; i++) {
output += i + " = " + values[i] + "\r\n";
}
alert (output);
}

Maybe not the most elegant, but it works
const inp = "af00b9e00f70"
const out = inp.match(/.{1,2}/g).map(a=>a=="00"?"_":a).join("").split("_");
console.log(out);

put dash after every n character during input from keyboard

$('.creditCardText').keyup(function() {
var foo = $(this).val().split("-").join(""); // remove hyphens
if (foo.length > 0) {
foo = foo.match(new RegExp('.{1,4}', 'g')).join("-");
}
$(this).val(foo);
});
I found this tutorial on putting dash after every 4 character from here my question is what if the character interval is not constant like in this example it is only after every 4 what if the interval is 3 characters "-" 2 characters "-" 4 characters "-" 3 characters "-" so it would appear like this 123-12-1234-123-123.

In this case, it is more convenient to just write normal code to solve the problem:
function format(input, format, sep) {
var output = "";
var idx = 0;
for (var i = 0; i < format.length && idx < input.length; i++) {
output += input.substr(idx, format[i]);
if (idx + format[i] < input.length) output += sep;
idx += format[i];
}
output += input.substr(idx);
return output;
}
Sample usage:
function format(input, format, sep) {
var output = "";
var idx = 0;
for (var i = 0; i < format.length && idx < input.length; i++) {
output += input.substr(idx, format[i]);
if (idx + format[i] < input.length) output += sep;
idx += format[i];
}
output += input.substr(idx);
return output;
}
$('.creditCardText').keyup(function() {
var foo = $(this).val().replace(/-/g, ""); // remove hyphens
// You may want to remove all non-digits here
// var foo = $(this).val().replace(/\D/g, "");
if (foo.length > 0) {
foo = format(foo, [3, 2, 4, 3, 3], "-");
}
$(this).val(foo);
});
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<input class="creditCardText" />
While it is possible to do partial matching and capturing with regex, the replacement has to be done with a replacement function. In the replacment function, we need to determine how many capturing group actually captures some text. Since there is no clean solution with regex, I write a more general function as shown above.

You can split it using a regular expression. In this case, I'm using a expression to check for non-spaces with interval 3-2-4-3.
The RegExp.exec will return with a "match" array, with the first element containing the actual string. After removing the first element of the match, you can then join them up with dashes.
var mystring = "123121234123"
var myRegexp = /^([^\s]{3})([^\s]{2})([^\s]{4})([^\s]{3})$/g
var match = myRegexp.exec(mystring);
if (match)
{
match.shift();
mystring = match.join("-")
console.log(mystring)
}

Per further comments, the op clarified they need a fixed interval for when to insert dashes. In that case, there are several ways to implement it; I think regular expression would probably be the worst, in other words, overkill and overly complication solution.
Some simpler options would be to create a new character array, and in a loop append character by character, adding a dash too every time you get to the index you want. This would probably be the easiest to write and grok after the fact, but a little more verbose.
Or you could convert to a character array and use an 'insert into array at index'-type function like splice() (see Insert Item into Array at a Specific Index or Inserting string at position x of another string for some examples).

Pass the input value and the indexes to append the separator, first, it will remove the existing separators then just append separators on positions indexes.
export function addSeparators(
input: string,
positions: number[],
separator: string
): string {
const inputValue = input.replace(/-/g, '').split(''); // remove existing separators and split characters into array
for (let i = 0; i < inputValue.length; i++) {
if (positions.includes(i)) inputValue.splice(i, 0, separator);
}
return inputValue.join('');
}

Word Array to String

how to do this in Javascript or Jquery?
Please suggest in 2 steps:
1.- Word Array to Single Byte Array.
2.- Byte Array to String.
Maybe this can help:
function hex2a(hex) {
var str = '';
for (var i = 0; i < hex.length; i += 2)
str += String.fromCharCode(parseInt(hex.substr(i, 2), 16));
return str;
}

What you are trying to achieve is already implemented in CryptoJS. From the documentation:
You can convert a WordArray object to other formats by explicitly calling the toString method and passing an encoder.
var hash = CryptoJS.SHA256("Message");
alert(hash.toString(CryptoJS.enc.Base64));
alert(hash.toString(CryptoJS.enc.Hex));
Honestly I have no idea why you want to implement that yourself... But if you absolutely need to do it "manually" in the 2 steps you mentioned, you could try something like this:
function wordToByteArray(wordArray) {
var byteArray = [], word, i, j;
for (i = 0; i < wordArray.length; ++i) {
word = wordArray[i];
for (j = 3; j >= 0; --j) {
byteArray.push((word >> 8 * j) & 0xFF);
}
}
return byteArray;
}
function byteArrayToString(byteArray) {
var str = "", i;
for (i = 0; i < byteArray.length; ++i) {
str += escape(String.fromCharCode(byteArray[i]));
}
return str;
}
var hash = CryptoJS.SHA256("Message");
var byteArray = wordToByteArray(hash.words);
alert(byteArrayToString(byteArray));
The wordToByteArray function should work perfectly, but be aware that byteArrayToString will produce weird results in almost any case. I don't know much about encodings, but ASCII only uses 7 bits so you won't get ASCII chars when trying to encode an entire byte. So I added the escape function to at least be able to display all those strange chars you might get. ;)
I'd recommend you use the functions CryptoJS has already implemented or just use the byte array (without converting it to string) for your analysis.

How can I parse a string in Javascript?

I have string looking like this:
01
02
03
99
I'd like to parse these to make them into strings like:
1. 2. 3. 99. etc.
The numbers are a maximum of 2 characters. Also I have to parse some more numbers later in the source string so I would like to learn the substring equivalent in javascript. Can someone give me advice on how I can do. Previously I had been doing it in C# with the following:
int.Parse(RowKey.Substring(0, 2)).ToString() + "."
Thanks

Why, parseInt of course.
// Add 2 until end of string
var originalA = "01020399";
for (var i = 0; i < originalA.length; i += 2)
{
document.write(parseInt(originalA.substr(i, 2), 10) + ". ");
}
// Split on carriage returns
var originalB = "01\n02\n03\n99";
var strArrayB = originalB.split("\n");
for (var i = 0; i < strArrayB.length; i++)
{
document.write(parseInt(strArrayB[i], 10) + ". ");
}
// Replace the leading zero with regular expressions
var originalC = "01\n02\n03\n99";
var strArrayC = originalC.split("\n");
var regExpC = /^0/;
for (var i = 0; i < strArrayC.length; i++)
{
document.write(strArrayC[i].replace(regExpC, "") + ". ");
}
The other notes are that JavaScript is weakly typed, so "a" + 1 returns "a1". Additionally, for substrings you can choose between substring(start, end) and substr(start, length). If you're just trying to pull a single character, "abcdefg"[2] will return "c" (zero-based index, so 2 means the third character). You usually won't have to worry about type-casting when it comes to simple numbers or letters.
http://jsfiddle.net/mbwt4/3/

use parseInt function.
parseInt(09) //this will give you 9
var myString = parseInt("09").toString()+". "+parseInt("08").toString();

string = '01\n02\n03\n99';
array = string.split('\n');
string2 = '';
for (i = 0; i < array.length; i++) {
array[i] = parseInt(array[i]);
string2 += array[i] + '. ';
}
document.write(string2);

var number = parseFloat('0099');
Demo

Substring in JavaScript works like this:
string.substring(from, to);
where from is inclusive and to is exclusive. You can also use slice:
string.slice(from, to)
where from is inclusive and to is exclusive. The difference between slice and substring is with slice you can specify negative numbers. For example, from = -1 indicates the last character. from(-1, -3) would give you the last 2 characters of the string.
With both methods if you don't specify end then you will get all the characters to the end.
Paul

Ii they are always 2 digits how about;
var s = "01020399";
var result = []
for (var i = 0; i < s.length; i+=2)
result.push(parseInt(s.substr(i, 2), 10) + ".")
alert( result[2] ) // 3.
alert( result.join(" ") ) // 1. 2. 3. 99.