Push a date to an array with moment js nodejs-CodePudding

I'm writing a function in NodeJs in which getting 2 dates returns an array with all dates in the range. Instead, I'm getting an array that adds to it the same date and deletes itself every time.

For example: Getting start date 1/11/2026 and end date 3/11/2026 it should return [1/11/2026, 2/11/2026, 3/11/2026] now it does: [1/11/2026],[2/11/2026, 2/11/2026],[3/11/2026, 3/11/2026, 3/11/2026]

I tried moving out from the while the format but I turn it to string I tried having 2 arrays and use spread operator but didn't succeed

Here is my code:

const dateList = ({ start, end }) => {
    let now = moment(start);
    const end = moment(end);
    let dates = [];
    while (now.format('YYYY-MM-DD') <= end.format('YYYY-MM-DD')) {
        dates.push(now);
        now = now.add(1, 'days');
    }
    return dates;
}

CodePudding user response：

Moment use instance of object

your variable now is an instance of moment date so if you you push it in your array and set his day to 1 the instance in your array get this change too because it's the same instance. You need to push a clone of your moment instance.

const dateList = ({ start, end }) => {
    let now = moment(start);
    const end = moment(end);
    let dates = [];
    while (now.format('YYYY-MM-DD') <= end.format('YYYY-MM-DD')) {
        dates.push(now.clone());
        now = now.add(1, 'days');
    }
    return dates;
}

and you can use moment query to test if end is after now.

while(now.format('YYYY-MM-DD') <= end.format('YYYY-MM-DD')) => while(now.isSameOrBefore(end))

final code :

const dateList = ({ start, end }) => {
    let now = moment(start);
    const end = moment(end);
    let dates = [];
    while (now.isSameOrBefore(end)) {
        dates.push(now.clone());
        now = now.add(1, 'days');
    }
    return dates;
}

CodePudding user response：

const dateList = ({ start, end }) => {
    let now = moment.utc(start);
    end = moment.utc(end);
    let dates = [];
    while (now.isValid() && end.isValid() && now.isSameOrBefore(end, 'day') /* end day inclusive */) {
        dates.push(now);
        now = moment(now).add(1, 'days'); // add 1 day on a new instance 
    }
    return dates;
}

console.log(dateList({start: '2026-05-12', end: '2026-05-14'}))

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