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3 While Loops into a Single Loop?

I have to remove the commas, periods, and hyphens from an HTML text value. I do not want to write all 3 of these while loops, instead I only want one loop (any) to do all of this.
I already tried a while with multiple && and if else nested inside but i would always only just get the commas removed.
while(beg.indexOf(',') > -1)
{
beg = beg.replace(',','');
document.twocities.begins.value= beg;
}
while(beg.indexOf('-') > -1)
{
beg = beg.replace('-','');
document.twocities.begins.value= beg;
}
while(beg.indexOf('.') > -1)
{
beg= beg.replace('.','');
document.twocities.begins.value= beg;
}

You can do all this without loops by using regex.
Here is an example of removing all those characters using a single regex:
let str = "abc,d-e.fg,hij,1-2,34.56.7890"
str = str.replace(/[,.-]/g, "")
console.log(str)

No loops are necessary for this in the first place.
You can replace characters in a string with String.replace() and you can determine which characters and patterns to replace using regular expressions.
let sampleString = "This, is. a - test - - of, the, code. ";
console.log(sampleString.replace(/[,-.]/g, ""));

A single call to the replace function and using a regular expression suffice:
document.twocities.begins.value = beg = beg.replace(/[,.-]/g, "");
Regular expressions are a pattern matching language. The pattern employed here basically says "every occurrence of one of the characters ., ,, -)". Note that the slash / delimits the pattern while the suffix consists of flags controlling the matching process - in this case it is g (global) telling the engine to replace each occurrence ( as opposed to the first only without the flag ).
This site provides lots of info about regular expressions, their use in programming and implementations in different programming environments.
There are several online sites to test actual regular expression and what they match (including explanations), eg. Regex 101.
Even more details ... ;): You may use the .replace function with a string as the first argument (as you did in your code sample). However, only the first occurrence of the string searched for will be replaced - thus you would have to resort to loops. Specs of the .replace function (and of JS in general) can be found here.

Use regex like below.
let example = "This- is a,,., string.,";
console.log(example.replace(/[-.,]+/g, ""));

How to write regexp for finding :smile: in javascript?

I want to write a regular expression, in JavaScript, for finding the string starting and ending with :.
For example "hello :smile: :sleeping:" from this string I need to find the strings which are starting and ending with the : characters. I tried the expression below, but it didn't work:
^:.*\:$

My guess is that you not only want to find the string, but also replace it. For that you should look at using a capture in the regexp combined with a replacement function.
const emojiPattern = /:(\w+):/g
function replaceEmojiTags(text) {
return text.replace(emojiPattern, function (tag, emotion) {
// The emotion will be the captured word between your tags,
// so either "sleep" or "sleeping" in your example
//
// In this function you would take that emotion and return
// whatever you want based on the input parameter and the
// whole tag would be replaced
//
// As an example, let's say you had a bunch of GIF images
// for the different emotions:
return '<img src="/img/emoji/' + emotion + '.gif" />';
});
}
With that code you could then run your function on any input string and replace the tags to get the HTML for the actual images in them. As in your example:
replaceEmojiTags('hello :smile: :sleeping:')
// 'hello <img src="/img/emoji/smile.gif" /> <img src="/img/emoji/sleeping.gif" />'
EDIT: To support hyphens within the emotion, as in "big-smile", the pattern needs to be changed since it is only looking for word characters. For this there is probably also a restriction such that the hyphen must join two words so that it shouldn't accept "-big-smile" or "big-smile-". For that you need to change the pattern to:
const emojiPattern = /:(\w+(-\w+)*):/g
That pattern is looking for any word that is then followed by zero or more instances of a hyphen followed by a word. It would match any of the following: "smile", "big-smile", "big-smile-bigger".

The ^ and $ are anchors (start and end respectively). These cause your regex to explicitly match an entire string which starts with : has anything between it and ends with :.
If you want to match characters within a string you can remove the anchors.
Your * indicates zero or more so you'll be matching :: as well. It'll be better to change this to + which means one or more. In fact if you're just looking for text you may want to use a range [a-z0-9] with a case insensitive modifier.
If we put it all together we'll have regex like this /:([a-z0-9]+):/gmi
match a string beginning with : with any alphanumeric character one or more times ending in : with the modifiers g globally, m multi-line and i case insensitive for things like :FacePalm:.
Using it in JavaScript we can end up with:
var mytext = 'Hello :smile: and jolly :wave:';
var matches = mytext.match(/:([a-z0-9]+):/gmi);
// matches = [':smile:', ':wave:'];
You'll have an array with each match found.

split on words except when phrase contains that word

I am trying to split where clauses, I want to split text on AND|OR|NOT except when NOT is in the 'phrase' NOT IN or NOT LIKE or IS NOT NULL.
1st example:
DEVLDATE IS NOT NULL AND STATUS = D AND PICKUPDATE IS NULL
I expect 3 segments, splitting on the AND's, but not on the NOT in this instance.
2nd ex:
(NOT (STATUS IN ('A','X') )) AND LINEHAUL = 0
I want to split on this NOT & AND, also expecting 3 segments in this instance
I'm trying this look ahead from another almost similar example but it is not splitting at all. I have next to zero regex experience. Not sure what I'm missing or if it's even possible.
Thanks in advance.
var ignoreRegex = /(?!.*\b([NOT IN]|[NOT LIKE]|[NOT BETWEEN]|[IS NOT NULL])\b)(?=.*\b(AND|OR|NOT)\b)/g
var filterArray = filterBy.split(new RegExp(ignoreRegex));

Try with:
\b(AND|OR|NOT(?!\s+NULL|IN|LIKE))\b
DEMO
About your regex:
(?!.*\b([NOT IN]|[NOT LIKE]|[NOT BETWEEN]|[IS NOT NULL])\b)(?=.*\b(AND|OR|NOT)\b
[NOT IN] - this is character class [...] it will match character
which you put in in, so it can match: N,T,etc. not whole
word/sentence,
([NOT IN]|[NOT LIKE]|[NOT BETWEEN]|[IS NOT NULL]) - this whole part actually can match only one character, because it doesn't use any quantifires or intervals, it doesn't work as you expect at all,
so whole regex should match: some text with AND, OR or NOT, but if line within which the part was matched doesn't consist letters and spaces included in character classes..... so it will not match anything probably.

Regex pattern does not work properly.. but only in Extjs / Javascript

I've built a regex pattern to check the strength of passwords:
(?=^.{8,15}$)((?=.*\d)(?=.*[A-Z])(?=.*[a-z])|(?=.*\d)(?=.*[^A-Za-z0-9])(?=.*[a-z])|(?=.*[^A-Za-z0-9])(?=.*[A-Z])(?=.*[a-z])|(?=.*\d)(?=.*[A-Z])(?=.*[^A-Za-z0-9]))^.*
It forces the user to use a password which characters originate from at least 3 of the 4 following categories:
at least 1 upper case character
at least 1 lower case character
at least 1 numerical character
at least 1 special character / symbol
Note: It also enforces a min and max length {8,15}
The pattern works fine on a server side PHP script and I've also tested it with multiple javascript Regex-tester-tools (e.g. http://www.regular-expressions.info/javascriptexample.html). Everything looks perfect so far...
BUT, if I'm using it inside of a simple Extjs textfield validator, the validator only returns TRUE, if I'm using all 4 categories.
validator: function (value) {
var pattern =
'(?=^.{8,15}$)'+
'((?=.*\d)(?=.*[A-Z])(?=.*[a-z])|' +
'(?=.*\d)(?=.*[^A-Za-z0-9])(?=.*[a-z])|' +
'(?=.*[^A-Za-z0-9])(?=.*[A-Z])(?=.*[a-z])|' +
'(?=.*\d)(?=.*[A-Z])(?=.*[^A-Za-z0-9]))^.*';
if (value.match(pattern)) {
return true;
} else {
return this.i18n.invalidPassword;
}
}
And now, I'm running out of ideas...

You're setting up the pattern incorrectly:
var pattern = new RegExp(
'(?=^.{8,15}$)'+
'((?=.*\\d)(?=.*[A-Z])(?=.*[a-z])|' +
'(?=.*\\d)(?=.*[^A-Za-z0-9])(?=.*[a-z])|' +
'(?=.*[^A-Za-z0-9])(?=.*[A-Z])(?=.*[a-z])|' +
'(?=.*\\d)(?=.*[A-Z])(?=.*[^A-Za-z0-9]))^.*'
);
Note the \\ instead of \. If you don't do that, the \ will be gone by the time the regular expression code gets to it. You could alternatively use native regex syntax, but there's no way to break that up across multiple lines.
edit — specifically, the \\ before the \d occurrences in your regex. If you don't double the backslash, then the regular expression will just see a lower-case "d".

javascript url-safe filename-safe string

Looking for a regex/replace function to take a user inputted string say, "John Smith's Cool Page" and return a filename/url safe string like "john_smith_s_cool_page.html", or something to that extent.

Well, here's one that replaces anything that's not a letter or a number, and makes it all lower case, like your example.
var s = "John Smith's Cool Page";
var filename = s.replace(/[^a-z0-9]/gi, '_').toLowerCase();
Explanation:
The regular expression is /[^a-z0-9]/gi. Well, actually the gi at the end is just a set of options that are used when the expression is used.
i means "ignore upper/lower case differences"
g means "global", which really means that every match should be replaced, not just the first one.
So what we're looking as is really just [^a-z0-9]. Let's read it step-by-step:
The [ and ] define a "character class", which is a list of single-characters. If you'd write [one], then that would match either 'o' or 'n' or 'e'.
However, there's a ^ at the start of the list of characters. That means it should match only characters not in the list.
Finally, the list of characters is a-z0-9. Read this as "a through z and 0 through 9". It's a short way of writing abcdefghijklmnopqrstuvwxyz0123456789.
So basically, what the regular expression says is: "Find every letter that is not between 'a' and 'z' or between '0' and '9'".

I know the original poster asked for a simple Regular Expression, however, there is more involved in sanitizing filenames, including filename length, reserved filenames, and, of course reserved characters.
Take a look at the code in node-sanitize-filename for a more robust solution.

For more flexible and robust handling of unicode characters etc, you could use the slugify in conjunction with some regex to remove unsafe URL characters
const urlSafeFilename = slugify(filename, { remove: /"<>#%\{\}\|\\\^~\[\]`;\?:#=&/g });
This produces nice kebab-case filenemas in your url and allows for more characters outside the a-z0-9 range.

Here's what I did. It works to convert full sentences into a decently clean URL.
First it trims the string, then it converts spaces to dashes (-), then it gets rid of anything that's not a letter/number/dash
function slugify(title) {
return title
.trim()
.replace(/ +/g, '-')
.toLowerCase()
.replace(/[^a-z0-9-]/g, '')
}
slug.value = slugify(text.value);
text.oninput = () => { slug.value = slugify(text.value); };
<input id="text" value="Foo: the old #Foobîdoo!! " style="font-size:1.2em">
<input id="slug" readonly style="font-size:1.2em">

I think your requirement is to replaces white spaces and aphostophy `s with _ and append the .html at the end try to find such regex.
refer
http://www.regular-expressions.info/javascriptexample.html