Sort array of days in ascending order

Question

I have an array that contains unique strings of day names. The day names will be in random order. - eg:

["Sun 10am", "Sat 4pm", "Sat 10am", "Wed 3pm", "Sun 4pm"]

I want to use javascript to sort that array so that it will be in ascending order.

["Wed 3pm", "Sat 10am", "Sat 4pm", "Sun 10am", "Sun 4pm"]

Can anybody suggest the best way to do that?

Thank you

Answer 1

• You can create a object with days names as keys and values increasing from 1 to 7.

• Create a helper function which takes second part of string i.e 3pm,10am.. as input and add 12 to result if its pm

• Also divide the result by 24 so first sort should happen on days.
• Use the sort() function and for each value add the time index(which will be always less than 1) to the day index(1,2,3...) and subtract it for both value.

const arr = ["Sun 10am", "Sat 4pm", "Sat 10am", "Wed 3pm", "Sun 4pm"];


function getTime(str){
  let time = str.slice(0,-2);
  let isAm = str.includes('am');
  return (isAm ? +time : +time + 12)/24
}

function sortTime(arr){
  let days = {
    Mon:1,
    Tue:2,
    Wed:3,
    Thur:4,
    Fri:5,
    Sat:6,
    Sun:7
  }
  return arr.slice().sort((a,b) => {
    let [day1,time1] = a.split(' ');
    let [day2,time2] = b.split(' ');
    return (days[day1] + getTime(time1)) - (days[day2] + getTime(time2)) 
  })
  
}

console.log(sortTime(arr))

Answer 2

You could take an object for the values of the day and sort by the time.

const
    getTime = string => {
        var [day, hour, meridian] = string.match(/^(\D{3}) (\d+)(am|pm)/).slice(1),
            days = { Mon: 1, Tue: 2, Wed: 3, Thu: 4, Fri: 5, Sat: 6, Sun: 7 };

        return days[day] * 24 + +hour + (meridian === 'pm' && 12) + (hour === '12' && -12);
    };
var array = ["Sun 10am", "Sat 4pm", "Sat 10am", "Wed 3pm", "Sun 4pm", "Sat 12pm", "Sat 12am"];

array.sort((a, b) => getTime(a) - getTime(b));

console.log(array);