Match only unicode letters

Question

i have the following regex that allows only alphabets :

     /[a-zA-Z]+/

     a = "abcDF"
     if (a.match(/[a-zA-Z]+/) == a){
        //Match
     }else{
        //No Match
     } 

How can I do this using p{L} (universal - any language like german, english etc.. )

What I tried :

  a.match(/[p{l}]+/)
  a.match(/[\p{l}]+/)
  a.match(/p{l}/)
  a.match(/\p{l}/)

but all returned null for the letter a = "aB"

Answer 1

Starting with ECMAScript 2018, JavaScript finally supports Unicode property escapes natively.

For older versions, you either need to define all the relevant Unicode ranges yourself. Or you can use Steven Levithan's XRegExp package with Unicode add-ons and utilize its Unicode property shortcuts:

var regex = new XRegExp("^\\p{L}*$")
var a = "abcäöüéèê"
if (regex.test(a)) {
    // Match
} else {
    // No Match
}

Answer 2

If you are willing to use Babel to build your javascript then there's a babel-plugin I have released which will transform regular expressions like /^\p{L}+$/ or /\p{^White_Space}/ into a regular expression that browsers will understand.

This is the project page: https://github.com/danielberndt/babel-plugin-utf-8-regex

Answer 3

You may use \p{L} with the modern ECMAScript 2018+ compliant JavaScript environments, but you need to remember that the Unicode property classes are only supported when you pass u modifier/flag:

a.match(/\p{L}+/gu)
a.match(/\p{Alphabetic}+/gu)

will match all occurrences of 1 or more Unicode letters in the a string.

NOTE that \p{Alphabetic} (\p{Alpha}) includes all letters matched by \p{L}, plus letter numbers matched by \p{Nl} (e.g. Ⅻ – a character for the roman number 12), plus some other symbols matched with \p{Other_Alphabetic} (\p{OAlpha}).

There are some things to bear in mind though when using u modifier with a regex:

• You can use Unicode code point escape sequences such as \u{1F42A} for specifying characters via code points. Normal Unicode escapes such as \u03B1 only have a range of four hexadecimal digits (which equals the basic multilingual plane) (source)
• "Characters of 4 bytes are handled correctly: as a single character, not two 2-byte characters" (source)
• Escaping requirements to patterns compiled with u flag are more strict: you can't escape any special characters, you can only escape those that can actually behave as special characters. See HTML input pattern not working.