Replace numbers to 3 decimal places using RegEx - regex

Question

I need to replace only numbers that are decimal to 3 places.
The following example is working fine.
Output look like this:
0.000
But i can type 0..
How can i do only one decimal point (.) 0.000
Here is my directive:
app.directive('allowDecimalNumbers', function () {
return {
restrict: 'A',
link: function (scope, elm, attrs, ctrl) {
elm.on('keypress', function (event) {
var $input = $(this);
var value = $input.val();
value = value.replace(/[^0-9\.]/g, '')
if(value == "" && event.which == 46) {
return false;
}
var findsDot = new RegExp(/\./g)
var containsDot = value.match(findsDot)
if (containsDot != null && ([46, 110, 190].indexOf(event.which) > -1)) {
event.preventDefault();
return false;
}
var arrValue = value.split('.');
if (value.split('.').length == 2) {
if(value.split('.')[1].length > 2) {
event.preventDefault();
return false;
}
}
$input.val(value);
if (event.which == 64 || event.which == 16) {
// numbers
return false;
}
else if (event.which >= 48 && event.which <= 57 || event.which == 46) {
// numbers
return true;
}
else {
event.preventDefault();
return false;
}
});
}
}});
Here is my html:
<input type="number" allow-decimal-numbers ng-model="length1" >

Answer 1

Note that validation can cause problem depending on locale, in french decimal separator is , and input type="number" prevents . to be typed.
could make it working removing code, note that . doesn't need to be escaped when it is in a character set ( between [ and ])
var app = angular.module('app', []);
app.directive('allowDecimalNumbers', function () {
return {
restrict: 'A',
link: function (scope, elm, attrs, ctrl) {
elm.on('keydown', function (event) {
var $input = $(this);
var value = $input.val();
if ([8, 13, 16, 27, 37, 38, 39, 40, 46].indexOf(event.which) > -1) {
// backspace, enter, shift, escape, arrows, delete
return true;
} else if ( (event.which >= 48 && event.which <= 57 ||
event.which >= 96 && event.which <= 105) && !value.match(/[.,]\d{3}/)) {
// numbers
return true;
} else if ([46, 110, 190, 188].indexOf(event.which) > -1 && !value.match(/[.,]/)) {
// dot and numpad dot
return true;
} else {
event.preventDefault();
return false;
}
});
}
}
});
Note that a digit can't be inserted after there's a decimal separator followed by three digit but we can't check where the digit is inserted even if it's in front.