In Uni§

See primary documentation in context for method codes

method codes(Uni:D: --> Int:D)

Returns the number of codepoints in the invocant.

In Cool§

See primary documentation in context for routine codes

sub codes(Str(Cool))
method codes()

Coerces the invocant (or in sub form, its argument) to Str, and returns the number of Unicode code points.

say 'møp'.codes;    # OUTPUT: «3␤»

The same result will be obtained with

say +'møp'.ords;    # OUTPUT: «3␤»

ords first obtains the actual codepoints, so there might be a difference in speed.