Develop Reference

nativeElement.value is NaN if there is a comma

I'm trying to set the number of decimals at 2 in an input. When I type a comma in it, the value becomes NaN so I would like get my number instead of this.
TS
#ViewChild('number') input;
limitNbOfDecimals() {
var regex =
this.form.number.search(/^(\d+(?:[\.\,]\d{0,2})?)$/) == 0
? true
: false;
if (regex == false) {
// Convert the value to a number
var nb: number = +this.input.nativeElement.value;
//set decimals at 2
this.input.nativeElement.value = nb.toFixed(2);
}
}
HTML
<input class="form-control" type="text" [(ngModel)]="form.number"
#number
name="number"
(input)="limitNbOfDecimals()"
/>
EDIT
I manage to add a comma in the number but if I try to add more than 2 decimals after it removes the numbers after the comma like 1,11 -> 1

This isn't a full answer, in the sense of having a total solution, but hopefully helps you get to one (and it's too long for a comment).
The spec at https://html.spec.whatwg.org/multipage/input.html#number-state-(type=number) states:
This specification does not define what user interface user agents
are to use; user agent vendors are encouraged to consider what would
best serve their users' needs. ..... a user agent designed for the
French market might display the value with apostrophes between
thousands and commas before the decimals, and allow the user to enter
a value in that manner, internally converting it to the submission
format described above.
It would seem that the only sure way - if you don't have control over what browsers your users have - of ensuring they can type numbers in the format they are used to in their local setting is to take input as type text and on each keystroke check that they have typed something valid (as you have defined it) and when they submit it convert to a decimal number.
Searching provides code for doing this, depending on exactly what your requirement is for the number formats though you may be better off coding it from scratch.

To add more than 2 decimal values, you need to tell like .toFixed(4) etc..

regex check for Float number -> not ending and stars with decimal point

I am facing issues with regex pattern for Float number -> that should not end or stars with decimal points..
I have tried following regex patter.. that is
regex = /^\d*\.?\d*$/
// on doing
regex.test(11.)
regex.test(.11)
// it is returning true in checking
// I need to make this as false, comment will be much helpful
thank you.

You should bear in mind that regex only works with strings. When you pass a non-string variable as input to a RegExp, it will first coerce it to a string type.
Have a look:
console.log(11. , 'and', .11); // => 11 and 0.11
So, the actual string values you pass to your ^\d*\.?\d*$ regex are 11 and 0.11 that can be matched with the given pattern. Actually, ^\d*\.?\d*$ is a regex that is usually used for a very loose live number input validation, e.g. see How to make proper Input validation with regex?.
What you want is to implement a final, on-submit validation pattern, so that it could not pass strings like 11. and .11. There have been lots of threads discussing this kind of regex:
Regular expression for floating point numbers
regular expression for finding decimal/float numbers?
Basically, for validation, you will need something like
/^\d+(?:\.\d+)?$/.test(input_string)
/^[0-9]+(?:\.[0-9]+)?$/.test(input_string)
/^[0-9]+(?:\.[0-9]{1,2})?$/.test(input_string) // Some need to only allow 1 or 2 fractional digits
/^[0-9]{1,3}(?:\.[0-9]{2})?$/.test(input_string) // 1-3 digits in the integer part and two required in the fractional part

Alpaca JS doesn't take into consideration if the regex pattern contains length limit

I am building a web application, using alpaca.js. I notice a problem when using regex patterns. If the pattern contains length it is not taken into consideration. For example this pattern "[0-9]{5}" should permit only 5 numbers, but it validates the numbers and not the length. To fix this I added min and max length, but it is a big problem if i have this kind of pattern ^[0-9]{1,3}([a-zA-Z]?)$.
Did somebody faced this issue before? Thanks

What you do is correct but, this will be used for schema validation and in your example you maybe need a mask rather than a regex. The mask will allows a user to more easily enter fixed width input where you would like them to enter the data in a certain format (dates,phone numbers, etc)
"options": {
"fields": {
"cap": {
"maskString": "99999" // 9 is a number, and here the mask will supports 5 digits
}
}
}
To use the maskString option you need first to import/add the Masked Input Plugin (the website is down, you could grab it from CDNJS or github)
For more details on maskString see Example 4 in Alpaca text field documentation.
For more details on Masked Input Plugin see this github repository.
And here's a fiddle for your example.
Hope this helps you.

Regex - creating an input/textarea that correctly interprets numbers

Im designing a conversion website where i perform calculations on inputted numbers and i need my input or textarea to receive and interpret numbers entered in different fashions
like:
Entry = 3,000,000.1111
Interpreted value = 3000000.1111
or
Entry = 3000000.1111
Interpreted value = 3000000.1111
and I want to include a second input for European decimal notation
(or if possible have the same input do both)
Entry = 3.000.000,1111 (comma acts a decimal, decimal as separator)
Interpreted value = 3000000.1111
I wonder how I could do this. I suspect from some of my research that I could use regex.
Also should i use an input or a textarea? I want to limit the size of the number to 40 places.
It seems the textarea Im currently using won't recognize any values after a comma when a comma is used. I realized this is due to parseFloat. So I need to remove the commas using .replace() before parsing. But what do I do in the instance of European notation where the comma IS the decimal point? I suspect I should use regex to identify if a number is in comma decimal notation or standard decimal point notation and then outline the appropriate replacement behavior based on that. Any ideas how to write regex to identify a number between .0000000001 and 1,000,000,000,000,000 by only the separator and decimal point? What about when the entry doesn't use either? 12000 for example. Any help with this would be appreciated. Using HTML5 and Javascript. I am not using a form and am new at this. This is my first web page so please be patient with my questions.
I was thinking about this:
input = //value from textarea as a string
if(/REGEX which determines that the structure of the number is N,NNN.NN/.test(input)){
input = input.replace(/\,/,""); //replace the commas with nothing
}
else if(/REGEX which determine that structure of the number is N.NNN,NN/.test(input){
input = input.replace(/\./,""); //replace the decimal point separators with nothing
input = input.replace(/\,/,".");//replace the comma decimal with a point decimal
}
else{
//input unchanged assuming is NNNN without decimal
}
number = parseFloat(input);
I want to keep the possibility open for them to enter large numbers and also to use numbers less than one to 10 decimal places. Thanks to those who contributed.
Best,RP

I believe this should handle everything:
^[1-9](?:\d{0,2}(?:([,.])\d{3})*|\d+)(?:(?!\1)[,.]\d+)?$
You're treading on complicated territory here. Also, the above RegEx does not allow for values less than "1".
Basically, the RegEx does the following:
Allows for no thousandths separators ("," or ".") but ensures if they are used that they occur in the correct places.
Allows for either "," or "." to be used as both thousandths/cents separators, but ensures that the cents separator is not the same as the thousandths separator.
Requires the string equivalent number to begin with any digit other than "0".
To implement this you could attach an event listener to your form element(s) and use JS to do a simple .test.
After reading further, I think I misinterpreted your goal originally. I assumed you simply wanted to validate these values with a RegEx. I also assumed you're trying to work with currency (ie. two decimal places). However, fret not! You can still utilize my original answer if you really want.
You mentioned input and textarea which are both form elements. You can attach a listener to these element(s) looking for the input, change, and/or keyup events. As a part of the callback you can run the .test method or some other functionality. Personally, I would rethink how you want to handle input. Also, what's your actual goal here? Do you really need to know the thousandths separator or keep track of it? Why not just disallow any characters other than the one decimal point/comma and digits?
Also, parsing numbers like .0000000001 as a float is a terrible idea. You will lose precision very quickly if you do any sort of calculations such as multiplication, division, power, etc. You're going to have to figure out a different method to do this like storing the number to the right separately and as integers instead then go from there.
I can help you if you describe what you're trying to do in better detail.

jQuery zip masking for multiple formats

I have a requirements for masking a zip field so that it allows the classic 5 digits zip (XXXXX) or 5 + 4 format (XXXXX-XXXX).
I could so something like:
$('#myZipField').mask("?99999-9999");
but the complication comes from the fact that dash should not be showing if the user puts in only 5 digits.
This is the best I came up with so far - I could extend it to auto-insert the dash when they insert the 6th digit but the problem with this would be funny behavior on deletion (I could stop them from deleting the dash but it would patching the patch and so forth, it becomes a nightmare):
$.mask.definitions['~']='[-]';
$("#myZipField").mask("?99999~9999", {placeholder:""});
Is there any out of the box way of doing this or do I have to roll my own?

You don't have to use a different plug-in. Just move the question mark, so that instead of:
$('#myZipField').mask("?99999-9999");
you should use:
$('#myZipField').mask("99999?-9999");
After all, it isn't the entire string which is optional, just the - and onward.

This zip code is actually simple, but when you have a more complex format to handle, here is how it's solved with the plugin (from the demo page):
var options = {onKeyPress: function(cep, e, field, options){
var masks = ['00000-000', '0-00-00-00'];
mask = (cep.length>7) ? masks[1] : masks[0];
$('.crazy_cep').mask(mask, options);
}};
$('.crazy_cep').mask('00000-000', options);

If you're using jQuery already, there are probably hundreds of plugins for masks etc, for example:
http://www.meiocodigo.com/projects/meiomask/
So I don't think you'd have to roll your own

When you use jQuery Inputmask plugin and you want to use 4 or 5 digit values for zip code you should use:
$('#myZipField').inputmask("9999[9]");

Why not have the field be transparent, and have a text object behind it with the form in light grey? So they see #######-#### in the background, and then rig it so the letters dissapear as they type. At that point, it suggests that they should enter a dash if they want to put the extra four, right? Then, you could just rig the script to autoinsert the hyphen if they mess up and type 6 numbers?