如何在 javascript 中返回两个对象

Question

举个例子

我有两个 arrays

const tempData = [
          { day: "Mon", temp: 33.6 },
          { day: "Tue", temp: 34.6 },
          { day: "Wed", temp: 33.1 },
          { day: "Fri", temp: 35.6 }
        ];
const coughData = [
          { day: "Mon", count: 2 },
          { day: "Wed", count: 1 },
          { day: "Thur", count: 1 },
          { day: "Fri", count: 3 },
          { day: "Sat", count: 1 }
        ]; 

我需要将这些 arrays 合并为一个，以便如果日期匹配，则计数值添加到 object 如果不匹配，则将两个对象添加到数组中。

不知道解释是不是很清楚，但是

预期的结果应该是这样的：

const data = [
          { day: "Mon", temp: 33.6, count: 2 },
          { day: "Tue", temp: 34.6 },
          { day: "Wed", temp: 33.1, count: 1 },
          { day: "Thur", count: 1 },
          { day: "Fri", temp: 35.6, count: 3 },
          { day: "Sat", count: 1 }
        ];

我正在尝试像这样使用 map function 但不明白如果它们不匹配我该如何返回这两个对象：

const data = tempData.map(temp => {
          coughData.map(cough => {
            if (temp.day === cough.day) {
              return (temp.count = cough.count);
            } else {
              return cough;
            }
          });
          return temp;
        });

Answer 1

您可以在 object 中收集按day分组的所有数据，并将值作为结果集。

 const addToCollection = (collection, key) => o => Object.assign(collection[o[key]]??= {}, o), tempData = [{ day: "Mon", temp: 33.6 }, { day: "Tue", temp: 34.6 }, { day: "Wed", temp: 33.1 }, { day: "Fri", temp: 35.6 }], coughData = [{ day: "Mon", count: 2 }, { day: "Wed", count: 1 }, { day: "Thur", count: 1 }, { day: "Fri", count: 3 }, { day: "Sat", count: 1 }], collection = {}; tempData.forEach(addToCollection(collection, 'day')); coughData.forEach(addToCollection(collection, 'day')); console.log(Object.values(collection));

 .as-console-wrapper { max-height: 100%;important: top; 0; }

Answer 2

您可以先合并 arrays 的对象，然后使用 .reduce .reduce()和Map来累积值。 Map 可以由day属性键入，这将允许您将相关的 object 属性组合在一起。 然后，您可以使用Array.from()将 Map 转换回对象数组，如下所示：

 const tempData = [{ day: "Mon", temp: 33.6 }, { day: "Tue", temp: 34.6 }, { day: "Wed", temp: 33.1 }, { day: "Fri", temp: 35.6 }]; const coughData = [{ day: "Mon", count: 2 }, { day: "Wed", count: 1 }, { day: "Thur", count: 1 }, { day: "Fri", count: 3 }, { day: "Sat", count: 1 }]; const arr = [...tempData, ...coughData]; const result = Array.from(arr.reduce((map, {day, ...rest}) => { const seen = map.get(day) || {day}; return map.set(day, {...seen, ...rest}); }, new Map).values()); console.log(result);

Answer 3

let newArray = Array();
let longer = (tempData.length <= coughData.length) ? coughData.length : 
tempData.length;
for(let i = 0, j = 0; i < longer; ++i, ++j) {
    newArray.push(Object.assign(coughData[i], tempData[j]));
}

打印到控制台：

[ { day: 'Mon', count: 2, temp: 33.6 },
{ day: 'Tue', count: 1, temp: 34.6 },
{ day: 'Wed', count: 1, temp: 33.1 },
{ day: 'Fri', count: 3, temp: 35.6 },
{ day: 'Sat', count: 1 } ]

Answer 4

 const tempData = [ { day: "Mon", temp: 33.6 }, { day: "Tue", temp: 34.6 }, { day: "Wed", temp: 33.1 }, { day: "Fri", temp: 35.6 } ]; const coughData = [ { day: "Mon", count: 2 }, { day: "Wed", count: 1 }, { day: "Thur", count: 1 }, { day: "Fri", count: 3 }, { day: "Sat", count: 1 } ]; const tempRes = [...tempData, ...coughData]; const result = tempRes.reduce((acc, curr) => { const { day, ...rest } = curr; acc[day] = acc[day]? Object.assign({}, acc[day], rest): curr return acc; }, {}) console.log(Object.values(result))

 .as-console-wrapper { max-height: 100%;important: top; 0; }

Answer 5

您可以使用 Object.assign() javascript function。 Object.assign() 方法用于将一个或多个源对象的所有可枚举属性的值复制到目标 object。 此方法将返回目标 object

像这样：

 const target = { a: 1, b: 2 }; const source = { b: 4, c: 5 }; const returnedTarget = Object.assign(target, source); console.log(target); // expected output: Object { a: 1, b: 4, c: 5 } console.log(returnedTarget); // expected output: Object { a: 1, b: 4, c: 5 }

https://developer.mozilla.org/pt-BR/docs/Web/JavaScript/Reference/Global_Objects/Object/assign