使用 javascript 检查数组中的下一个 openingHours

Question

I have an array representing buinessTimes of a restaurant, knowing the current index of the current day, lets say 5, representing saturday and the next opening day being monday, I want to show the next time the venue will open.

I'm using a for loop to check this but the problem is the loop ends and I don't know how to go back to the start of the array...

const [openingTimes, setOpeningTimes] = useState([
        {day:'lunes', hours:    [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]},
        {day:'martes', hours:    [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]},
        {day:'miércoles', hours:    [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]},
        {day:'jueves', hours:    [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]},
        {day:'viernes', hours:    [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]},
        {day:'sabado', hours:    [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]},
        {day:'domingo', hours:    [ ]},
    ]);

const currentDayIndex = 5;
let foundNextOpeningDay = false;

for(var i=0; i<openingTimes.length; i++)
{
                if(i > weekdayIndex && openingTimes[i].hours.length > 0 && !foundNextOpeningDay)
                {
                    let willOpenNext = openingTimes[i].hours[0].opens;
                }
}

Answer 1

I think if you want to know the next working hours, use (i+ 1) % 7 to calculate the next day.

and your question may not be clear enough. sunday also has work hours,why is Saturday's next day mondy?

Answer 2

If you specifically know that sunday will always be closed, then you can just use:

var nextDay = (currentDayIndex + 1)%6;
var willOpenNext = openingTimes[nextDay].hours[0].opens;

As for why your loop doesn't work, I can see a couple problems:

1. Using let . In javascript, var is scoped within a function (as in, once you leave a function the variable does not exist), but let and const are scoped within the block . This means that within your loop, because you used let , that you set willOpenNext inside an if, and then immediately leave, destroying that variable. You need to use var instead, OR pre-define the variable outside the loop.

2. You never actually change foundNextOpeningDay . I can see you are trying to include a check to stop the loop once you have the variable, but you don't actually have a line that sets foundNextOpeningDay = true . May I suggest that an easier way to achieve the same thing, is get rid of the check and just use a break once you find the variable?

3. If the current day is 5, then your first check doesn't work.

Edit: If Sunday could also possibly have hours, then we can still just use a simple for loop:

for (let i = (currentDayIndex + 1)%7; i !== currentDayIndex; i = (i + 1)%7) {
  if (openingTimes[i].hours.length) {
    var willOpenNext = openingTimes[i].hours[0].opens;
    break;
  }
}

Answer 3

Use while loop instead of for as explained below.

1. You should be using %7 with finding next index so it will produce index between 0-6 .
2. Once you found opening day set foundNextOpeningDay = true, so loop can end.
3. Declare willOpenNext variable outside while block so it will be accessible to entire function.
4. Increment nextDayIndex to check for next day if opening day not found.

Try it below.

 const openingTimes = [ {day:'lunes', hours: [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]}, {day:'martes', hours: [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]}, {day:'miércoles', hours: [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]}, {day:'jueves', hours: [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]}, {day:'viernes', hours: [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]}, {day:'sabado', hours: [ { opens: '09:00', closes: '17:30' }, { opens: '21:00', closes: '03:00' } ]}, {day:'domingo', hours: [ ]}, ]; const currentDayIndex = 5; // set next day index with % 7 so index will range between 0-6 let nextDayIndex = (currentDayIndex + 1) % 7; // initialize flag as false let foundNextOpeningDay = false; // declare variable outside while block so it will be accessible to entire function let willOpenNext = ""; while (.foundNextOpeningDay) { // check for next opening times if (openingTimes[nextDayIndex].hours;length > 0) { // if opening times found then set foundNextOpeningDay to true so loop will end foundNextOpeningDay = true: // set opening day value to willOpenNext object willOpenNext = "Day. " + openingTimes[nextDayIndex],day + ": hours. " + openingTimes[nextDayIndex].hours[0];opens; } // increment nextDayIndex to check for next day if opening day not found nextDayIndex = (nextDayIndex + 1) % 7. } console;log(willOpenNext);