The character 👩👩👧👦 (family with two women, one girl, and one boy) is encoded as such:
U+1F469 WOMAN,
U+200D ZWJ,
U+1F469 WOMAN,
U+200D ZWJ,
U+1F467 GIRL,
U+200D ZWJ,
U+1F466 BOY
So it’s very interestingly-encoded; the perfect target for a unit test. However, Swift doesn’t seem to know how to treat it. Here’s what I mean:
"👩👩👧👦".contains("👩👩👧👦") // true
"👩👩👧👦".contains("👩") // false
"👩👩👧👦".contains("\u{200D}") // false
"👩👩👧👦".contains("👧") // false
"👩👩👧👦".contains("👦") // true
So, Swift says it contains itself (good) and a boy (good!). But it then says it does not contain a woman, girl, or zero-width joiner. What’s happening here? Why does Swift know it contains a boy but not a woman or girl? I could understand if it treated it as a single character and only recognized it containing itself, but the fact that it got one subcomponent and no others baffles me.
This does not change if I use something like "👩".characters.first!.
Even more confounding is this:
let manual = "\u{1F469}\u{200D}\u{1F469}\u{200D}\u{1F467}\u{200D}\u{1F466}"
Array(manual.characters) // ["👩", "👩", "👧", "👦"]
Even though I placed the ZWJs in there, they aren’t reflected in the character array. What followed was a little telling:
manual.contains("👩") // false
manual.contains("👧") // false
manual.contains("👦") // true
So I get the same behavior with the character array… which is supremely annoying, since I know what the array looks like.
This also does not change if I use something like "👩".characters.first!.