瞬间在几个月内的差异

Question

我正在尝试在两个日期之间在几个月中解决差异，而无需考虑几天。

我试图使用 Math.ceil ，但是如果2022年的那一天比2021年的一天领先，那么我得到了2个月而不是1个月的差异。

const diff = moment([2022, 0, 1]).diff(moment([2021, 11, 3]), 'months', true);
console.log(diff); // 0.935483870967742, expected 1

const diffCeil = Math.ceil(
  moment([2022, 0, 3]).diff(moment([2021, 11, 1]), 'months', true)
);
console.log('diffCeil', diffCeil); // 2, expected 1

// Inaccurate diff doesn't work when 2021 day is bigger than in 2022
const inacurrateDiff = moment([2022, 0, 3]).diff(moment([2021, 11, 1]), 'months');
console.log('inacurrateDiff', inacurrateDiff); // 1, as expected
const inacurrateDiff2 = moment([2022, 0, 1]).diff(moment([2021, 11, 3]), 'months');
console.log('inacurrateDiff2', inacurrateDiff2); // 0, expected 1

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我确实在有没有 diff 的第三个精确参数的情况下尝试了。

Answer 1

您可以使用 startof（d，'月份'）比较几个月的开始：

a.startOf('month').diff(b.startOf('month'), 'month');

Answer 2

您会得到2，因为您使用的是 Math.ceil ，它总是将分数值提高到下一个整数。

这里没有一个正确的答案，您必须决定要计算的部分月份。

例如，如果仅想要月份，请使用 Math.floor 而不是 Math.ceil 。如果您想将最多1.5个月的任何内容计算为一个1.5个月及以上为2的东西，请使用 MATH.ROUND 。或者，您可以设置自己的阈值，例如1.2（这要做更多的工作，但没有那么多）。

示例：

function example(date1, date2) {
    const rawDiff = date1.diff(date2, "months", true);
    const diffFloored = Math.floor(rawDiff);
    const diffRounded = Math.round(rawDiff);
    const diffCeiled = Math.ceil(rawDiff);
    const neg = rawDiff < 0;
    const fractional = neg
        ? rawDiff + Math.trunc(rawDiff)
        : rawDiff - Math.trunc(rawDiff);
    const diffOnePointTwo = Math.abs(fractional) > 0.2
        ? Math.ceil(rawDiff)
        : Math.floor(rawDiff);

    console.log({
        date1: date1.toString(),
        date2: date2.toString(),
        rawDiff,
        diffFloored,
        diffRounded,
        diffCeiled,
        diffOnePointTwo,
    });
}

example(
    moment([2022, 0, 1]),
    moment([2021, 11, 3])
);
example(
    moment([2022, 0, 3]),
    moment([2021, 11, 1])
);
example(
    moment([2022, 0, 10]),
    moment([2021, 11, 1])
);

.as-console-wrapper {
    max-height: 100% !important;
}

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只有您和您的项目才能说出您要使用的定义。