我如何使数组值的上半部分成为钥匙，而另一半成为这些键的值？

Question

Closed. This question needs to be more focused. It is not currently accepting answers.

---

想要改进此问题吗？更新该问题，因此它仅针对一个问题编辑此帖子。

闭合 2年前。

Answer 1

您可以使用 code> array.prototype。 flatmap ：

const flatMapToEntry = (key, index, array) => {
  const length = array.length / 2;
  if (index >= length) {
    return [];
  }
  const value = array[index + length];
  return [{ [key]: value }];
};
const result = array.map(o => o.value).flatMap(flapMapToEntry);

Answer 2

这是使用评论中提供的相同逻辑的答案。这具有相关的描述以帮助更好地理解。

const getMyObject = arr => {

  // first compuate the half-length "lenBy2" of given array

  const lenBy2 = Math.floor(arr.length / 2);

  // return the "result" as an object

  return Object

    .fromEntries(                 // generate object from key-value pairs below

      arr.map(                    // iterate "arr" to obtain key-value pairs

        ({ value }, idx) => (     // get the index "idx" and de-structure to access "value"

          idx < lenBy2            // if index less than half-length "lenBy2"

          ? [                     // return key-value pair as a 2-element array

            value,                // [ "banana", "yellow" ], for example

            arr[idx + lenBy2]?.value

          ]

          : []                    // if index >= half-length, return empty array

        )

      ).filter(                   // filter key-value pairs to retain only non-empty ones

        x => x.length == 2

      )

    );

};
// below are steps only to generate results for various test cases

// the original array from the question

const array1 = [{value: 'banana'}, {value: 'apple'}, {value: 'yellow'}, {value: 'red'}];
// test-case 2 - an array with 3 pairs

const array2 = [

  {value: 'banana'}, {value: 'apple'}, {value: 'tomato'},

  {value: 'yellow'}, {value: 'green'}, {value: 'red'}

];
// mismatched array where the fruit "orange" has no matching color

const array3 = [

  {value: 'banana'}, {value: 'apple'}, {value: 'orange'},

  {value: 'yellow'}, {value: 'red'}

];
// mismatched array where the color "orange" has no matching fruit

const array4 = [

  {value: 'banana'}, {value: 'apple'},

  {value: 'yellow'}, {value: 'red'}, {value: 'orange'}

];
// iterate over the various test case arrays &

// console.log the result

[array1, array2, array3, array4].forEach((arr, idx) =>

  console.log(

    `\n***---> test case ${idx + 1} <---***\n`,

    'given array: