Hmm I just tested ‘zya’ for じゃ and it worked. To enable multiple answers for the same kana, I switched the data structure from a key/value pair of strings
'じゃ': 'ja'
to a string:array one:
'じゃ': ['ja', 'zya'],
So it’s definitely there!
This is the entire data structure at present for compound katakana:
export const compoundKatakana = {
'キャ': ['kya'], 'キュ': ['kyu'], 'キョ': ['kyo'],
'シャ': ['sha', 'sya'], 'シュ': ['shu', 'syu'], 'ショ': ['sho', 'syo'],
'チャ': ['cha', 'tya'], 'チュ': ['chu', 'tyu'], 'チョ': ['cho', 'tyo'],
'ニャ': ['nya'], 'ニュ': ['nyu'], 'ニョ': ['nyo'],
'ヒャ': ['hya'], 'ヒュ': ['hyu'], 'ヒョ': ['hyo'],
'ミャ': ['mya'], 'ミュ': ['myu'], 'ミョ': ['myo'],
'リャ': ['rya'], 'リュ': ['ryu'], 'リョ': ['ryo'],
'ギャ': ['gya'], 'ギュ': ['gyu'], 'ギョ': ['gyo'],
'ジャ': ['ja', 'zya'], 'ジュ': ['ju', 'zyu'], 'ジョ': ['jo', 'zyo'],
'ヂャ': ['ja', 'dya'], 'ヂュ': ['ju', 'dyu'], 'ヂョ': ['jo', 'dyo'],
'ビャ': ['bya'], 'ビュ': ['byu'], 'ビョ': ['byo'],
'ピャ': ['pya'], 'ピュ': ['pyu'], 'ピョ': ['pyo']
};
Adding new ones is just a matter of adding to this data.