Moment JS 看似返回随机日期

Question

Moment JS 正在返回一个随机日期。

我正在尝试在 react-native 项目中创建日历。我创建了这个循环来倒数从今天开始的天数。我已经连接了我的控制台，并试图清楚地展示我是如何尝试调试的。

减法似乎无法识别循环，并且 i 值似乎停留在 16。

任何帮助将不胜感激。 This is the code that is causing all the fussThis is the output in the console

Answer 1

Per Moment.js，时刻是可变的。克隆执行日期数学之前的时刻

https://momentjs.com/guides/#/lib-concepts/mutability/

在执行 .add()、.subtract() 等操作时，您需要创建一个新的时刻实例或克隆现有的实例。

const moment = require("moment");

const today = moment();

// count back N days
const N = 3;
let i = 1;
let days = [];


// #1 - Create a new moment instance from today and add -i days
while (i <= N) {
  const day = moment(today).add(-i, "days");
  days.push(day);
  i++;
}

console.log("Approach #1");
console.log({ days });

// #2 - A moment is mutable. So we use add() to mutate today by -1 days each iteration, clone the instance, and push to array
i = 0;
days = [];
while (i < N) {
  const day = today.add(-1, "days").clone();
  days.push(day);
  i++;
}

console.log("Approach #2");
console.log({ days });