Regular Expression Flags

[Kikobeats]

Unicode Flag (u)

The unicode flag was recently added:

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicode

It should be used by default!

/^.$/.test('a') //✅
/^.$/.test('🐶') //❌
/^.$/u.test('🐶') //✅

dot all flag (s)

By default, . matches any character except for line terminators:

/foo.bar/u.test('foo\nbar');
// → false
(It doesn’t match astral Unicode symbols either, but we fixed that by enabling the u flag.)

ES2018 introduces dotAll mode, enabled through the s flag. In dotAll mode, . matches line terminators as well.

/foo.bar/su.test('foo\nbar');
// → true

__

both flags can be used as the new standard

Reference:

• https://flaviocopes.com/javascript-regular-expressions/
• https://mathiasbynens.be/notes/es-unicode-property-escapes
• https://mathiasbynens.be/notes/es-regexp-proposals
• https://github.com/zeeshanu/learn-regex
• https://www.youtube.com/watch?v=mIWCLOftfRw