删除特定对象后在对象中从数组中设置新序列
我的目标： 我需要在 sequenceIndex 中有一个连续的数字序列，它是我对象中的一个值。
因此，当我删除特定对象时，其他对象的序列索引当然不再连续了。正在根据特定值检查我删除的对象，以查看数组中是否还有其他对象共享相同的值（第二个 if 语句）。如果是这样，那么应该有一个连续的新值集。
输出是 if 语句中的迭代器对于所有操作的对象始终相同。
由此：
const objectsArray = [
{
folder: "folderName",
documents: [
{
id: 0,
sequenceIndex: "0",
documentType: "letter"
},
{
id: 1,
sequenceIndex: "1",
documentType: "letter"
},
{
id: 2,
sequenceIndex: "2",
documentType: "letter"
},
{
id: 3,
sequenceIndex: "3",
documentType: "letter"
}
]
}
];
通过删除 id 1 和 2，我想解决这个问题（请参阅连续序列索引）：
const desiredObjectsArray = [
{
folder: "folderName",
documents: [
{
id: 0,
sequenceIndex: "0",
documentType: "letter"
},
{
id: 3,
sequenceIndex: "1",
documentType: "letter"
}
]
}
];
到目前为止我的代码：
case ActionType.RemoveDocumentInSpecificFolder:
return state.map(file => {
// if in the correct folder remove the object with the delivered id
if (file.folder=== folder) {
remove(file.documents, {
id: action.payload.documents[0].id
});
// create newObjArray from objects which share a specific value and replace the sequence index by new value
const newObjArray = file.documents.map((obj: any) => {
// if the object has the specific value create new object with new sequenceIndex
if (obj.documentType === action.payload.documents[0].documentType) {
//poor attempt to create a sequence
let i = 0;
const correctedSequenceDocObject = { ...obj, sequenceIndex: i };
i++;
return correctedSequenceDocObject;
}
我希望有人能指导我朝着正确的方向前进。我也将永远感谢最佳实践的建议:)
Qyouu3回答
-
手掌心
正如评论：这是 .filter().map() 有用的经典案例。过滤数据，然后使用 .map((o, i) => ({ ...obj, sequenceIndex: i+1 }) )以下是示例：const objectsArray = [{ folder: "folderName", documents: [{ id: 0, sequenceIndex: "0", documentType: "letter" }, { id: 1, sequenceIndex: "1", documentType: "letter" }, { id: 2, sequenceIndex: "2", documentType: "letter" }, { id: 3, sequenceIndex: "3", documentType: "letter" } ]}];const ignoreIds = [1, 2]const updatedDocs = objectsArray[0].documents .filter(({ id }) => !ignoreIds.includes(id)) .map((doc, index) => ({ ...doc, sequenceIndex: index }));console.log(updatedDocs)现在让我们介绍您的尝试const newObjArray = file.documents.map((obj: any) => { // For all the unmatching objects, you will have undefined as object as you are using `.map` // This will make you `newObjArray: Array<IDocument | undefined>` which can break your code. if (obj.documentType === action.payload.documents[0].documentType) { // This will set it as 0 in every iteration making i as 0 always. let i = 0; const correctedSequenceDocObject = { ...obj, sequenceIndex: i }; i++; return correctedSequenceDocObject; } return { ...obj };});单循环的替代：主意：使用创建一个循环Array.reduce并将一个空白数组作为列表传递给它。添加一个检查并在其中将值推送到此列表。对于sequenceIndex，获取最后一个元素并获取其sequenceIndex. 添加一个并重新设置。const newObjArray = file.documents.reduce((acc: Array<IDocument>, obj: any) => { if (obj.documentType === action.payload.documents[0].documentType) { const sequenceIndex: number = (!!acc[acc.length - 1] ? acc[acc.length - 1].sequenceIndex : 1) + 1; acc.push({ ...obj, sequenceIndex }); } return acc;}); -
月关宝盒
你可以使用filter和map这样的东西const arr = [{folder: "folderName",documents: [{id: 0,sequenceIndex: "0",documentType: "letter"},{id: 1,sequenceIndex: "1",documentType: "letter"},{id: 2,sequenceIndex: "2",documentType: "letter"},{id: 3,sequenceIndex: "3",documentType: "letter"}]}];let getInSequence = (filterId) => { return arr[0].documents.filter(({ id }) => !filterId.includes(id)) .map((v, i) => ({ ...v, sequenceIndex: i }))}console.log(getInSequence([1, 2])) -
波斯汪
我现在用来解决这个问题的解决方案是： let count = 0; const newObject = file.documents.map(obj => { if (obj.documentType === firstDocument.documentType) { count++; return { ...obj, sequenceIndex: count - 1 }; } return obj; });由于不同的 documentType，提供的两个答案都无法处理不感兴趣的对象，因此他们删除了对象。使用此解决方案，我正在检查最后一个元素并增加计数，如果最后一个元素是相同的 documentType。
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相关分类
JavaScript