如何在某个属性更改后向数组添加新条目？

Question

我正在尝试在某个属性更改后向数组添加新条目，在我的例子中是“位置”更改。但是，我很难找到合适的方法，因为操作取决于数组中的下一个对象。

const initalData = [
  { storyID: 1, place: 12, type: "Story" },
  { storyID: 5, place: 12, type: "Story" },
  { storyID: 99, place: 45, type: "Story" }, 
  { storyID: 8, place: 31, type: "Story" },
  { storyID: 16, place: 31, type: "Story" },
  { storyID: 20, place: 45, type: "Story" },
  { storyID: 22, place: 45, type: "Story" },
];

const targetData = [
  { placeID: 12, type: "Place" }, // new added entry based on the next  "place"
  { storyID: 1, place: 12, type: "Story" },
  { storyID: 5, place: 12, type: "Story" },
  { placeID: 45, type: "Place" }, // // new added entry based on the next  "place"
  { storyID: 99, place: 45, type: "Story" },
  { placeID: 31, type: "Place" }, // new added entry based on the next  "place"
  { storyID: 8, place: 31, type: "Story" },
  { storyID: 16, place: 31, type: "Story" },
  { placeID: 45, type: "Place" },// new added entry based on the next  "place"
  { storyID: 20, place: 45, type: "Story" },
  { storyID: 22, place: 45, type: "Story" },
];

目前我已经将groupBy("place")视为一种可能的方法，但这里的最终数组结构并不是我所需要的。

Answer 1

这是实现

const initalData = [
    { storyID: 1, place: 12, type: "Story" },
    { storyID: 5, place: 12, type: "Story" },
    { storyID: 99, place: 45, type: "Story" },
    { storyID: 8, place: 31, type: "Story" },
    { storyID: 16, place: 31, type: "Story" },
    { storyID: 20, place: 45, type: "Story" },
    { storyID: 22, place: 45, type: "Story" },
];

let oldPlace = null;
let resultData = [];

for (let row of initalData) {
    if (row.place != oldPlace) {
        resultData.push({ placeID: row.place, type: "Place" });
        oldPlace = row.place;
    }
    resultData.push(row);
}

console.log (resultData);

如何在某个属性更改后向数组添加新条目？

How to add a new entry to an array after a certain property changes?

javascript

arrays

如何在某个 属性 更改后向数组添加新条目？

How to add a new entry to an array after a certain property changes?

javascript

arrays

如何在某个属性更改后向数组添加新条目？