JavaScript useful Date related (week,month,quarter) functions

As we all seen JavaScript is the most preferred programming language of the Internet.

Here are someuseful functions to iterate through the weeks / months / quarters in your code using simple JS functions.

    const weekRange = (num) => {

        // num defintion: -1 is pevious week, likewise -2,-3 OR only 1, 2 for upcoming weeks.

        let mydate = new Date();

        let mydate2 = new Date();

        num = num * 7; // 7 days per week * counter

        let x = mydate.getDate() - mydate.getDay() + 1; // +1 to set the first day of the week as Monday

        mydate.setDate(x + num);

        mydate.setHours(0, 0, 0); // setting the 0,0,0 to cover entire week right from day one midnight

        mydate2.setDate(x + num + 5 + 1); // +6 to calculatethe Saturday EOD

        mydate2.setHours(23, 59, 0); // setting 23,59 tp cover last day of the week till midnight

        return [mydate, mydate2]; //return array to compare the window with

    };

    const monthName = [

        "January",

        "February",

        "March",

        "April",

        "May",

        "June",

        "July",

        "August",

        "September",

        "October",

        "November",

        "December",

    ];

    const browseMonths = (num) => {

        // pass number of months you wish to add or subtract.

        let DateObj = new Date();

        DateObj.setMonth(DateObj.getMonth() + num);

        return DateObj;

    };

    const browseQuarter = (num) => {

        // num is ctr passed to calculate the future or past months

        let DateObj = new Date();

        let qstart = new Date();

        let qend = new Date();

        let quarter = "";

        num = parseInt(num);

        if (num !== 0) {

            DateObj.setMonth(DateObj.getMonth() + num * 3);

        } else {

            DateObj.setMonth(DateObj.getMonth());

        }

        const month = parseInt(DateObj.getMonth());

        if (month >= 0 && month <= 2) {

            quarter = "Q1 " + DateObj.getFullYear();

            //console.log(DateObj.toDateString());

            qstart = new Date(DateObj);

            qend = new Date(DateObj);

            qstart.setMonth(0);

            qstart.setDate(1);

            qstart.setHours(0, 0, 0);

            qend.setMonth(2);

            qend.setDate(31);

            qend.setHours(23, 59, 0);

        } else if (month >= 3 && month <= 5) {

            quarter = "Q2 " + DateObj.getFullYear();

            //console.log(DateObj.toDateString());

            qstart = new Date(DateObj);

            qend = new Date(DateObj);

            qstart.setMonth(3);

            qstart.setDate(1);

            qstart.setHours(0, 0, 0);

            qend.setMonth(5);

            qend.setDate(30);

            qend.setHours(23, 59, 0);

        } else if (month >= 6 && month <= 8) {

            quarter = "Q3 " + DateObj.getFullYear();

            //console.log(DateObj.toDateString());

            qstart = new Date(DateObj);

            qend = new Date(DateObj);

            qstart.setMonth(6);

            qstart.setDate(1);

            qstart.setHours(0, 0, 0);

            qend.setMonth(8);

            qend.setDate(30);

            qend.setHours(23, 59, 0);

        } else if (month >= 9 && month <= 11) {

            quarter = "Q4 " + DateObj.getFullYear();

            //console.log(DateObj.toDateString());

            qstart = new Date(DateObj);

            qend = new Date(DateObj);

            qstart.setMonth(9);

            qstart.setDate(1);

            qstart.setHours(0, 0, 0);

            qend.setMonth(11);

            qend.setDate(31);

            qend.setHours(23, 59, 0);

        } else {

            quarter = "";

        }

        return [quarter, qstart, qend];

    };