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js 二つの配列の差分を求める

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お題

二つの配列の差分を求める。

function diffArray(arr1, arr2) {
//write your code.
}
diffArray(["diorite", "andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]);

出力結果 例

[1, 2, 3, 5], [1, 2, 3, 4, 5] // [4]
[1, "calf", 3, "piglet"], [1, "calf", 3, 4] // ["piglet", 4]
[], ["snuffleupagus", "cookie monster", "elmo"] // ["snuffleupagus", "cookie monster", "elmo"]
[1, "calf", 3, "piglet"], [7, "filly"] // [1, "calf", 3, "piglet", 7, "filly"]

使ったもの

indexOf()
for文
if文
push()

考え方

・newArrを宣言してここに差分を代入する。
・for文にてarr1とarr2を比較して、indexOfが−1になった数値をnewArrにpushする。
for文二つで、arr1にあってarr2にないもの、arr2にあってarr1にないものをそれぞれpushする。
・return newArryで差分を返しておわり。

コード

function diffArray(arr1, arr2) {
  var newArr = [];
  for(var a = 0 ; a < arr1.length; a++){
    if(arr2.indexOf(arr1[a]) === -1 ){
      newArr.push(arr1[a]);
    }    
  }
  for(var b = 0; b < arr2.length; b++){
    if(arr1.indexOf(arr2[b]) === -1 ){
       newArr.push(arr2[b]);
       }
  }
  return newArr;
}
diffArray(["diorite", "andesite", "grass", "dirt", "pink wool", "dead shrub"], ["diorite", "andesite", "grass", "dirt", "dead shrub"]);

アロー関数を使ったコード

function diffArray(arr1, arr2) {
   return arr1.concat(arr2)
    .filter(item => !arr1.includes(item) || !arr2.includes(item));
}

他にもコードが浮かんだ方、コメントおまちしております。

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