Javascript でカタカナ->ひらがな変換とか全角英数->半角英数に変換とかのメモ

カタカナ->ひらがな変換

const katakanaToHiragana = (katakana) => {
  return katakana.replace(/[\u30a1-\u30f6]/g, (match) => {
    const chr = match.charCodeAt(0) - 0x60;
    return String.fromCharCode(chr);
  });
};

console.info(katakanaToHiragana('カタカナヴ'));
//-> かたかなゔ

全角英数->半角英数に変換

const zenkakuEisuToHankaku = (str) => {
  return str.replace(/[Ａ-Ｚａ-ｚ０-９]/g, (s) => {
    return String.fromCharCode(s.charCodeAt(0)-0xFEE0);
  });
};

console.info(zenkakuEisuToHankaku('ＡＢＣＤＥｆｇｈｉ１２３４５'));
//-> ABCDEfghi12345

文字列を半角数字のみに変換

const stringToOnlyNumbers = (str) => {
  return zenkakuEisuToHankaku(str).replace(/[^0-9]/g, '');
};

console.info(stringToOnlyNumbers('foo12bar34ＨＯＧＥ５６ｆｕｇａ７８'));
//-> 12345678

参考

• http://qiita.com/mimoe/items/855c112625d39b066c9a
• http://qiita.com/konweb/items/bdff25e7994f8014adcf