Question

Have following validation for year value from text input:

if (!year.match(new RegExp('\\d{4}'))){
    ...
}

RegExp equals null if numeric of digits from 0 to 3. It’s OK.
In case 4 digits it returns value.It’s OK.
In case more than 4 digits it returns value again,that it’s NOT OK.

Documentation says {n} declaration means exact number,but works like:

exact+

With such ugly validation it work’s fine:

if (!year.match(new RegExp('\\d{4}')) || year.length>4){
...
}

I wish to utilize RegExp object only.

Answer 1

Yes it would allow more than 4 digits since it would be a partial match use the ^ and $ to mark the beginning and the end of the string.

if (!year.match(new RegExp('^\\d{4}$'))){
    ...
}