removing all entries from an object before a certain index javascript

Question

I have an object which looks as so:

const hours = {
   Monday: ['9:00 am', '4:00 pm'],
   Tuesday: ['9:00 am', '4:00 pm'],
   Wednesday:['9:00 am', '3:00 pm']
   Thursday: ['9:00 am', '3:00 pm'],
   Friday: ['9:00 am', '3:00 pm'],
   Saturday: "Closed",
   Sunday: "Closed",
}

I then get the current day of the week in a string format:

  const d = new Date();
  let day = d.getDay();

  const daysOfWeek = {
    1: 'Monday',
    2: 'Tuesday',
    3: 'Wednesday',
    4: 'Thursday',
    5: 'Friday',
    6: 'Saturday',
    7: 'Sunday'
  }


  const currentDayString = daysOfWeek[day]

I now need to create a new object that has the current day, up until sunday.

ex output

if the day is 'Friday' the hours obj should be:


{
  Friday: ['9:00 am', '3:00 pm'],
  Saturday: "Closed",
  Sunday: "Closed"
}

How can I achieve this?

please add the data in literal notation. is the data sorted? — Nina Scholz, Mar 25 '22 at 21:22
iterate for(d=day; d<=7;d++) out[daysOfWeek[d]]=response[daysOfWeek[d]] — thst, Mar 25 '22 at 21:25
you have all the data you need. just a for loop should do as thst mentioined — cmgchess, Mar 25 '22 at 21:41

score 2 · Answer 1 · answered Mar 25 '22 at 21:43

Let today's day be d (ex: 'Monday', 'Tuesday') then, and serverData be data we are getting from server so,

let found=0;
let result={}

Object.keys(daysOfWeek).forEach(key => {
  if (found) {
    result[daysOfWeek[key]] = serverData[daysOfWeek[key]]
  };
  if (daysOfWeek[key] === d) {
    found = 1;
  }
})

score 0 · Answer 2 · answered Mar 25 '22 at 22:12

Let say your starting day is "thursday", your result object could never be like this :

{
  Thursday: (2) ['9:00 am', '3:00 pm'
  Friday: (2) ['9:00 am', '3:00 pm']
  Saturday: "Closed"
  Sunday: "Closed"
}

Cause JS orders an object alphabetically.

Try to push your results into an array like this (data been your server data):

let result = [];
for(let i=day; i <= Object.keys(daysOfWeek).length; i++)
{
     // result[daysOfWeek[i]] = data[daysOfWeek[i]]; // return object
     result.push(data[daysOfWeek[i]]); // return array
}

score 0 · Answer 3 · answered Mar 25 '22 at 22:20

If your input data always contain all the week days in the right order, you can simply use the object properties index to determine which day it is:

const data = {
  Monday: ['9:00 am', '4:00 pm'],
  Tuesday: ['9:00 am', '4:00 pm'],
  Wednesday: ['9:00 am', '3:00 pm'],
  Thursday: ['9:00 am', '3:00 pm'],
  Friday: ['9:00 am', '3:00 pm'],
  Saturday: 'Closed',
  Sunday: 'Closed',
};

const today = new Date().getDay();

const result = {};
Object.entries(data).forEach(([key, value], index) => {
  if (index >= today - 1) result[key] = value;
});

console.log(result);

score 0 · Answer 4 · answered Mar 25 '22 at 22:46

Can be done with reduce

const data = {
  Monday: ['9:00 am', '4:00 pm'],
  Tuesday: ['9:00 am', '4:00 pm'],
  Wednesday: ['9:00 am', '3:00 pm'],
  Thursday: ['9:00 am', '3:00 pm'],
  Friday: ['9:00 am', '3:00 pm'],
  Saturday: 'Closed',
  Sunday: 'Closed',
};

const day = new Date().toLocaleString('en', { weekday: 'long' });

const result = Object.entries(data).reduce((prev, [key, value]) => {
  if (key === day || day in prev) {
    prev[key] = value;
  }
  
  return prev;
}, {});

console.log(result);

Carsten Massmann · Answer 5 · 2022-03-26T04:12:03.457

The easiest way of doing it would be to step through some dates, starting with the current date dt. Show the opening times for the current day and then increment the date by one day. Repeat this process as long as wd!== "Sunday".

const opening={ // exactly as received from the server:
Friday:   ['9:00 am', '3:00 pm'],
Monday:   ['9:00 am', '4:00 pm'],
Saturday: "Closed",
Sunday:   "Closed",
Thursday: ['9:00 am', '3:00 pm'],
Tuesday:  ['9:00 am', '4:00 pm'],
Wednesday:['9:00 am', '3:00 pm']};

const dt=new Date();
do {
 var wd=dt.toLocaleString("en",{weekday:"long"});
 console.log(`${wd}: ${opening[wd]}`);
 dt.setDate(dt.getDate()+1);
} while(wd!=="Sunday") // stop after "Sunday"

Doing it this way we don't require any "order" of the properties in the opening object. Keep in mind that you cannot always rely on the order of properties in an object anyway!

score 0 · Accepted Answer · edited Mar 28 '22 at 16:50

My solution was to use a daysOfWeek object to bridge the data between hours and day by storing the keys of hours as the values of daysOfWeek and the keys of daysOfWeek to match any of the possible values of .getDay() (1-7 for each day of the week).

Works well for THIS particular use case.

const hours = {
   Monday: ['9:00 am', '4:00 pm'],
   Tuesday: ['9:00 am', '4:00 pm'],
   Wednesday: ['9:00 am', '3:00 pm'],
   Thursday: ['9:00 am', '3:00 pm'],
   Friday: ['9:00 am', '3:00 pm'],
   Saturday: "Closed",
   Sunday: "Closed"
};

const d = new Date();
let day = d.getDay(); // if Friday, day === 5


const daysOfWeek = [ 
  'Monday',
  'Tuesday',
  'Wednesday',
  'Thursday',
  'Friday',
  'Saturday',
  'Sunday'
];

let thisWeekHours = {};

for (let i = day - 1; i < 7; i++) { // i === 5, 6, 7 (day value will never exceed 7), -1 because the array start at 0 and date at 1
  const hoursKey = daysOfWeek[i] // hoursKey === 'Friday', 'Saturday', 'Sunday'
  thisWeekHours[hoursKey] = hours[hoursKey] // Setting property name to hoursKey, && value to hours at key of hoursKey
}

console.log(thisWeekHours);

For example, output for friday:

thisWeekHours = {
   'Friday': ['9:00', '3:00'],
   'Saturday': 'Closed',
   'Sunday': 'Closed'
}

Nice ! I just convert code to snippet to make it easier to people to test themself — Elikill58, Mar 28 '22 at 16:51

removing all entries from an object before a certain index javascript

6 Answers6