javascript - 根据多个键的重复值从对象数组中删除元素

Question

我有一个像这样的对象数组 -

var arr = [
    { type_id: "3", full_empty:"true", quantity:1},
    { type_id: "3", full_empty:"true", quantity:1},
    { type_id: "9", full_empty:"true", quantity:4},
    { type_id: "9", full_empty:"false", quantity:4},
    { type_id: "9", full_empty:"true", quantity:4},
    { type_id: "9", full_empty:"true", quantity:4},
    { type_id: "9", full_empty:"true", quantity:4}
];

我想删除具有相同 type_id 和 full_empty 值的重复项。结果应该是这样的 -

var arr = [
    { type_id: "3", full_empty:"true", quantity:1},
    { type_id: "9", full_empty:"true", quantity:4},
    { type_id: "9", full_empty:"false", quantity:4},
];

我已经搜索并找到了一些解决方案，但其中一些是用于删除重复键或仅基于一个键的重复值删除重复项。一些需要外部库。还有一些我无法理解的解决方案。有没有简单的方法可以在纯 JavaScript 中执行此操作？

编辑以便更好地理解 - 我已阅读此 question .该问题的公认答案是仅查找一个键的重复项。就我而言，我必须找到多个键的重复项。

Answer 1

您可以使用 Array.some() 来使用纯函数 和 Array.reduce() 将您的输入数组减少为不同元素的数组，如下所示

    var arr = [
        { type_id: "3", full_empty:"true", quantity:1},
        { type_id: "3", full_empty:"true", quantity:1},
        { type_id: "9", full_empty:"true", quantity:4},
        { type_id: "9", full_empty:"false", quantity:4},
        { type_id: "9", full_empty:"true", quantity:4},
        { type_id: "9", full_empty:"true", quantity:4},
        { type_id: "9", full_empty:"true", quantity:4}
    ];

    var a = arr.reduce(function (accumulator, current) {
      if (checkIfAlreadyExist(current)) {
        return accumulator
      } else {
        return accumulator.concat([current]);
      }
      
      function checkIfAlreadyExist(currentVal) {
        return accumulator.some(function(item){
          return (item.type_id === currentVal.type_id &&
                  item.full_empty === currentVal.full_empty);
        });
      }
    }, []);
        
    console.log(a);

简洁的 ES6 语法

可以使用 ES6 箭头函数和扩展运算符编写更简洁的 reduce，如下所示:

var arr = [
            { type_id: "3", full_empty:"true", quantity:1},
            { type_id: "3", full_empty:"true", quantity:1},
            { type_id: "9", full_empty:"true", quantity:4},
            { type_id: "9", full_empty:"false", quantity:4},
            { type_id: "9", full_empty:"true", quantity:4},
            { type_id: "9", full_empty:"true", quantity:4},
            { type_id: "9", full_empty:"true", quantity:4}
        ];

var a = arr.reduce((accumulator, current) => {
  if (checkIfAlreadyExist(current)) {
    return accumulator;
  } else {
    return [...accumulator, current];
  }

  function checkIfAlreadyExist(currentVal) {
    return accumulator.some((item) => {
      return (item.type_id === currentVal.type_id &&
              item.full_empty === currentVal.full_empty);
    });
  }
}, []);
            
console.log(a);