在每次更改数组 JS 后插入项目

Question

假设我有一个这样的数组：

var array = [{date: "2021-06-02", name: "Foo" /*... and more*/}]

现在我已经对数组进行了排序

array.sort(function (a, b) {
    var keyA = new Date(a.date),
        keyB = new Date(b.date);
    if (keyA < keyB) return -1; // a.date is before b.date
    if (keyA > keyB) return 1;  // other way around

    return 0;

});

现在我想在现在排序的数组中的每个新日期之后添加{type: "new date occured", date: "", name: "New Date!"}。

我怎么做？

Answer 1

你可以像下面这样使用

var array = [{date: "2021-06-02", name: "Foo" }, {date: "2021-06-01", name: "Bar" }, {date: "2021-06-05", name: "Hello" }]
array = array.sort(function (a, b) {
    var keyA = new Date(a.date),
        keyB = new Date(b.date);
    if (keyA < keyB) return -1; // a.date is before b.date
    if (keyA > keyB) return 1;  // other way around

    return 0;

});

console.log(array)

array.push({type: "new date occured", date: "", name: "New Date!"})

console.log(array)

[
  { date: '2021-06-01', name: 'Bar' },
  { date: '2021-06-02', name: 'Foo' },
  { date: '2021-06-05', name: 'Hello' }
]
[
  { date: '2021-06-01', name: 'Bar' },
  { date: '2021-06-02', name: 'Foo' },
  { date: '2021-06-05', name: 'Hello' },
  { type: 'new date occured', date: '', name: 'New Date!' }
]

Answer 2

我认为这回答了您的问题，尽管您实际上想要做什么还不清楚。

const array = [{date: "2021-06-02", name: "Foo" }, {date: "2021-06-01", name: "Bar" }, {date: "2021-06-05", name: "Hello" }];

function sortFunc(a, b) {
    var keyA = new Date(a.date),
        keyB = new Date(b.date);
    if (keyA < keyB) return -1; // a.date is before b.date
    if (keyA > keyB) return 1;  // other way around
    return 0;
}
array.sort(sortFunc);
console.log(array);

function alterDate(name, newDate) {
  const thisDate = array.find(d => d.name === name);
  if (!thisDate) return;
  thisDate.date = newDate;
  thisDate.type = "new date occured";
  array.sort(sortFunc);
}
alterDate("Bar", "2021-06-08");
console.log(array);

Answer 3

您说“插入之后”，所以在这里我从数组中的日期添加一个并使用它，为数组中的每个实例在当前对象之后插入一个新对象。我创建了一个示例数组来显示一个示例集。

鉴于您的问题有些模棱两可，这可能不是您想要的，但应该给您一个工作点。

我还冒昧地在原始数组中添加了 type:'old'，因此它们都具有相同的属性 - 如果您愿意，可以轻松删除。

var myArray = [{
  date: "2021-06-02",
  name: "Foo"
}, {
  date: "2021-06-06",
  name: "bar"
}, {
  date: "2021-06-12",
  name: "fiz"
}, {
  date: "2021-02-21",
  name: "feb"
}];

function compare(firstEl, secondEl) {
  let keyA = new Date(firstEl.date).getTime(),
    keyB = new Date(secondEl.date).getTime();
  if (keyA < keyB) return -1; // firstEl.date is before secondEl.date
  if (keyA > keyB) return 1; // other way around
  //equal
  return 0;
}

function getNewDate(olddate) {
  let nextDay = new Date(olddate);
  nextDay.setDate(nextDay.getDate() + 1);
  let dateString = nextDay
    .toISOString("en-CA")
    .split("T")[0];
  return dateString;
}
myArray.sort(compare);
// doing this just to show the 'old' with the same set of properties
myArray.forEach(function (element) {
  element.type = "old";
});
i = myArray.length - 1;

do {
  let replacecount = 0;
  let currItem = myArray[i];
  let nextDay = getNewDate(currItem.date);

  let newvalue = {
    type: 'new date occurred',
    date: nextDay,
    name: "newDate" + i
  };
  myArray.splice(i+1, 0, newvalue);
} while (i--)

console.log(myArray);