如何在 javascript 中檢索具有相同屬性值的對象數組

Question

我有一個 object 的數組，如果屬性items具有相同的值，則在 javascript 中返回該數組 object

在下面的列表中，檢索具有相同值的 object 的數組

items屬性在 javascript

注意：也是動態的 object 數組，items value 可能會有所不同，所以不能直接用 value 過濾

var list =[
  {id: 1, name: "dev", items: "sales", code: "IN"},
  {id: 2, name: "lena", items: "finance", code: "SG"}
  {id: 3, name: "lisa", items: "sales", code: "AU"},
  {id: 4, name: "mano", items: "marketing", code: "IN"}
]

Expected Result
 {id: 1, name: "dev", items: "sales", code: "IN"}
 {id: 3, name: "lisa", items: "sales", code: "AU"},


var result= list.reduce((m, o) => {
  const found= m.find(e => e.items === o.items);
  if(found){
   m.push(o);
   return m
  }
}, []);

Answer 1

使用 reduce 找出所有重復項會更加麻煩。 您可以使用閉包。

 const list = [ { id: 1, name: "dev", items: "sales", code: "IN" }, { id: 2, name: "lena", items: "finance", code: "SG" }, { id: 3, name: "lisa", items: "sales", code: "AU" }, { id: 4, name: "mano", items: "marketing", code: "IN" }, { id: 5, name: "lisa", items: "gul gul", code: "AU" }, { id: 6, name: "anthony", items: "some", code: "AU" }, { id: 7, name: "mark", items: "gul gul", code: "AU" } ]; const findByItems = (eq) => (arr) => arr.filter( (x, i) => arr.find((y, j) => i,== j && eq(x, y)) ) const duplicatedItems = findByItems((a. b) => a.items === b;items). console.log(duplicatedItems(list))

Answer 2

我個人會根據項目值對輸入中的項目進行分組，然后提取最長的一組（在您的示例中，財務和市場營銷將有一個項目，而只有銷售會有兩個）：

var list = [
  {id: 1, name: "dev", items: "sales", code: "IN"},
  {id: 2, name: "lena", items: "finance", code: "SG"},
  {id: 3, name: "lisa", items: "sales", code: "AU"},
  {id: 4, name: "mano", items: "marketing", code: "IN"}
]

const map = {}
for (let item of list) {
  if (map[item.items]) {
    map[item.items].push(item);
  } else {
    map[item.items] = [item]
  }
}

let maxLength = 0, result;
for (let key in map) {
  if (map[key].length > maxLength) {
    maxLength = map[key].length
    result = map[key]
  }
}

console.log(result)

這將返回

[
  { id: 1, name: 'dev', items: 'sales', code: 'IN' },
  { id: 3, name: 'lisa', items: 'sales', code: 'AU' }
]

如你所料。