[Javascript] 配列の重複を取り出す方法 - QiitaJavascriptでは標準でuniqueやdistinct関数がないので、配列の重複を取り出すいくつかの方法を紹介します。 Array.prototype.reduceを使う方法 const animals = ["cat", "cat", "dog", "mouse", "dog"]; const distinctAnimals = animals.reduce( (distinct, animal) => (distinct.indexOf(animal) !== -1) ? distinct : [...distinct, animal] , [] ) console.log(distinctAnimals) // ["cat", "dog", "mouse"] const animals = ["cat", "cat", "dog", "mouse", "dog"]; const
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