在 Typescript/Javascript [duplicate] 中将 Date[] 添加到 Date[][] 中的奇怪行为

问：

因此，我需要计算一组时间间隔，如下所示： 我决定为此使用 Date 类型，并编写了这段代码来测试：[8:00 - 8:10]

let todaysDate = new Date();
let startTime: Date = new Date(todaysDate.setHours(5, 0, 0));
let endTime: Date = new Date(todaysDate.setHours(6, 0, 0));
let start : number = startTime.getTime();
let interval: number = 600000;

let firstTime = new Date(startTime.getTime());
let secondTime = new Date(startTime.getTime() + interval);

let timeIntervalsArray: Date[][] = [];

while (secondTime.getTime() < endTime.getTime()) {
    firstTime.setTime(start);
    secondTime.setTime(firstTime.getTime() + interval);

    const times: Date[] = [firstTime, secondTime];
    timeIntervalsArray.push(times);
    start += interval;
}

console.log(timeIntervalsArray);

但是在记录 timeIntervalsArray 变量时，我得到数组中的所有变量都是相同的：

[LOG]: 
[[Date: "2023-04-22T05:50:00.722Z", Date: "2023-04-22T06:00:00.722Z"], 
[Date: "2023-04-22T05:50:00.722Z", Date: "2023-04-22T06:00:00.722Z"], 
[Date: "2023-04-22T05:50:00.722Z", Date: "2023-04-22T06:00:00.722Z"], 
[Date: "2023-04-22T05:50:00.722Z", Date: "2023-04-22T06:00:00.722Z"], 
[Date: "2023-04-22T05:50:00.722Z", Date: "2023-04-22T06:00:00.722Z"], 
[Date: "2023-04-22T05:50:00.722Z", Date: "2023-04-22T06:00:00.722Z"]]

我设法通过更改以下行来修复此行为：const times: Date[] = [firstTime, secondTime];const times: Date[] = [new Date(firstTime), new Date(secondTime)];

但我不明白这是如何工作的，就好像我是这样记录的一样：

while (secondTime.getTime() < endTime.getTime()) {
    firstTime.setTime(start);
    secondTime.setTime(firstTime.getTime() + interval);

    //Logging firstTime
    console.log(firstTime);
    console.log('As new date', new Date(firstTime));
    //

    const times: Date[] = [firstTime, secondTime];
    timeIntervalsArray.push(times);
    start += interval;
}

我得到相同的 Data 对象：

[LOG]: Date: "2023-04-22T05:00:00.718Z" 
[LOG]: "As new date",  Date: "2023-04-22T05:00:00.718Z" 

更奇怪的是 - 在记录 timeIntervalsArray 本身时：

while (secondTime.getTime() < endTime.getTime()) {
    firstTime.setTime(start);
    secondTime.setTime(firstTime.getTime() + interval);

    //Logging timeInterval
    console.log(timeIntervalsArray);
    //
    
    const times: Date[] = [firstTime, secondTime];
    timeIntervalsArray.push(times);
    start += interval;
}

Fist iteration : [LOG]: [] -> array is empty 
Second iteration : 
[LOG]: [[Date: "2023-04-22T05:10:00.241Z", Date: "2023-04-22T05:20:00.241Z"]] 
-> array has one element - [Date: "2023-04-22T05:10:00.241Z", Date: "2023-04-22T05:20:00.241Z"]

Third iteration : 
[LOG]: [[Date: "2023-04-22T05:20:00.241Z", Date: "2023-04-22T05:30:00.241Z"], 
[Date: "2023-04-22T05:20:00.241Z", Date: "2023-04-22T05:30:00.241Z"]] 
-> the fist element has been changed to 
[Date: "2023-04-22T05:20:00.241Z", Date: "2023-04-22T05:30:00.241Z"]
but it was 
[Date: "2023-04-22T05:10:00.241Z", Date: "2023-04-22T05:20:00.241Z"]

有人可以解释这种行为，因为我没有想法......