用来自另一个对象的值交换对象值。*Javascript*

Question

我的任务是编写一个函数，将元素的值与位于第二个对象内相同位置的值交换为。

{placeOne:10,placeTwo:20},{ten:"firstPlace",twenty:"secondPlace"}   

{placeOne:"firstPlace",placeTwo:"secondPlace"},{ten:10,twenty:20} // should equal this

我想尝试一种将对象值推入数组的方法，然后循环遍历对象，并将每个位置设置为数组中的位置。

但是我在同时遍历对象和数组时遇到了麻烦，所以我无法这样解决它。

这是我到目前为止所拥有的。

function swapObj(obj1,obj2){
  let obj1Arr = [];
  let obj2Arr = [];

  for(var i in obj1) {
    obj1Arr.push(obj1[i]);
  }

  for(var k in obj2) {
    obj2Arr.push(obj2[k])
  }

swapObj({placeOne:10,placeTwo:20,placeThree:30,}, 
        {ten:"firstPlace",twenty:"secondPlace",thirty:"thirdPlace"}
)

Answer 1

如果我正确理解了您的问题，就应该这样做(每一步都有一个注释)：

const swapValues = (a, b) => {
    // obtain arrays of entries ([key, value] pairs) of input objects
    // assuming the entries come in insertion order,
    // which is true in practice for all major JS engines
    const entriesA = Object.entries(a)
    const entriesB = Object.entries(b)

    // output is a pair of objects:
    // first with keys from a, but values from b
    //      at corresponding entry indices
    // second with keys from b, but values from a
    //      at corresponding entry indices
    // assuming both objects have the same number of entries
    //      (might want to check that)
    return entriesA.reduce(
        // for each entry from a with keyA, valueA and index
        (acc, [keyA, valueA], index) => {
            // get corresponding entry from b
            const entryB = entriesB[index]
            // with keyB and valueB
            const [keyB, valueB] = entryB
            // put valueB at keyA in the first output object
            acc[0][keyA] = valueB
            // put valueA at keyB in the second output object
            acc[1][keyB] = valueA

            return acc
        },
        // initially the output objects are empty:
        [{}, {}]
    )
}

console.log(swapValues(
    {placeOne: 10, placeTwo: 20},
    {ten: "a", twenty: "b"}
)) // -> [ { placeOne: 'a', placeTwo: 'b' }, { ten: 10, twenty: 20 } ]

您可能希望将其适应于您的JS版本。注意，没有发生任何输入对象的变异--您得到两个全新的对象(如果输入对象有嵌套对象作为值，它们可能与输入对象共享某种结构)。