I have 2 form fields in HTML namely Year and Week.

Once the user selects a Year and a week from the dropdowns, I want to display the month Name for the selected year and week.

Can anyone help me to get month name based on year and iso week numbers.

For example: If I selected year as 2022 and week no as 16, then the expected output is April as a month name.

This shoud be a function that returns the month name for a given year and week.

Below is my sampke code.

getMonthName() {
    const year  =  2022;
    const week  = 16;
    console.log(month);
  }

CodePudding user response：

Really interesting form. I came up with a solution like this;

I do not suggest you to divide per 4 weeks per month because not all months have 4 weeks. But from your input you always can now the day of year from number of week

numberOfWeek * 7 = numberOfDay

create a method :

const dateFromDay = (year, day = 1) => {
  const date = new Date(year, 0);
  return new Date(date.setDate(day));
}

// call the method with your inputs

const myDate = edateFromDay(2022,16*7); 
// here you will have the full date 

// if you want just the month than 
myDate.getMonth();

CodePudding user response：

Example: https://codesandbox.io/s/damp-wood-nynj7f?file=/src/app/app.component.ts

1. Create mapper for your months:
2. 4 weeks = 1 month, then get input value of week covert to number and divide 4. (Example: 16 / 4 === 4)
3. The result is a key of your mapper: months[divided result]

The best is a using Date libraries such as: dayjs, date-fns, moment, luxon or other.

const months = {
    1: "January",
    2: "February"
}

changeWeekHandler(e) {
   const week = parseInt(e.target.value)
   const month = Math.ceil(week / 4) // for round number to the upper (example: Math.ceil(0.25) -> 1)
   this[your input field] = months[month]
}

CodePudding user response：

The following will display the month name (short form) for the given ISO week number and year.

function getMonthName(week, year) {
let d =new Date(year,0,1 (week-1)*7);
d.getUTCDay()<5?d.setUTCDate(d.getUTCDate()-d.getUTCDay() 1):d.setUTCDate(d.getUTCDate() 8-d.getUTCDay());
return ("" d).split(" ")[1];
}

console.log(getMonthName(1,2022));
console.log(getMonthName(11,2022));
console.log(getMonthName(16,2022));