Add components.MergeClasses

[markuswustenberg]

Inspired by https://www.reddit.com/r/golang/comments/1g5mkcm/best_htmlcssjs_component_library/lsi038g/

Not sure this will be merged yet, WIP.

[apetsko]

Hi, just little faster implementation

var result []string
parts := strings.Split(strings.Join(classes, " "), " ")
for _, p := range parts {
	if p == "" || slices.Contains(result, p) {
		continue
	}
	result = append(result, p)
}
sort.Strings(result)
return strings.Join(result, " ")

[pdf]

I'm undecided if this is a good idea or not yet, but on the implementation, do we care about duplicates? The current implementation for Classes doesn't dedup.

If we do want dedup, this implentation significantly more efficient:

func MergeClasses(classes ...string) string {
        var results []string
        for _, c := range classes {
                results = append(results, strings.Split(c, " ")...)
        }

        sort.Strings(results)
        return Class(strings.Join(slices.Compact(results), " "))
}

BenchmarkDefaultNonOverlapping-16         370407              3789 ns/op            2558 B/op         11 allocs/op
BenchmarkDefaultOverlapping-16            292194              3917 ns/op            2670 B/op         11 allocs/op
BenchmarkApetskoNonOverlapping-16         588950              2366 ns/op            1552 B/op          9 allocs/op
BenchmarkApetskoOverlapping-16            408938              3022 ns/op            1728 B/op          9 allocs/op
BenchmarkSlicesNonOverlapping-16         1501532               800.7 ns/op          1104 B/op          5 allocs/op *
BenchmarkSlicesOverlapping-16             864552              1285 ns/op            1376 B/op          5 allocs/op *

If we don't care about duplicates, this func just becomes a simple return Class(strings.Join(classes, " ")) (unless class sorting is also important, I see that is part of the Classes implementation).