CODEWITHSUNDEEP
javascript
Giorgia Sambrotta
Giorgia Sambrotta

Reputation: 1223

calendar keep going on getting the previous month

I'm building my small calendar with plain javascript (so please no jquery) and I have trouble to make the prev month display So far this is my code for get previous month:

document.getElementById("prev-month").addEventListener("click", function(e) {
    console.log('first', prevMonth);
    prevMonth = monthNamesArray[currentMonth - 1]; //Array with all the month labels like ['Jan', 'Feb', 'Mar'];
    month.innerHTML = '<td>'+ prevMonth +'</td>'; //Here i replace the html cell where the month is display
    console.log('second', prevMonth); 
});

The console.log of the two debugger is: First click: first undefined second September(the previous month) Second click: first September second September

Why the during the second click the second console log didn't became second August ? Why the prevMonth go back just one month?

Any help, in particular an explanation, is really appreciated

Upvotes: 0

Views: 46

Answers (2)

Ayb4btu
Ayb4btu

Reputation: 3388

Is there any reason why you need prevMonth, as to keep it updating correctly you would ideally write it as:

currentMonth = monthNamesArray[(currentMonth==0)? 11 : currentMonth-1];

The ternary operator ensures that at January you don't go monthNamesArray[-1], but it instead wraps back to monthNamesArray[11].

EDIT: Both directions, the direction variable can be any size integer value, so you could go direction = -2 and it will go backwards 2 months. currentMonthIndex is the index for the current month 0 to 11.

var remainder = (currentMonthIndex + direction) % 12;
currentMonth = monthNamesArray[Math.floor(remainder >= 0 ? remainder : remainder + 12)];

Upvotes: 1

manji
manji

Reputation: 47978

You didn't update currentMonth, still points to october.

Upvotes: 1

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