CODEWITHSUNDEEP
javascripttypescriptdate
Joe Berthelot
Joe Berthelot

Reputation: 735

How to change variable to next string in an array

Code:

months = [
    'January',
    'February',
    'March',
    'April',
    'May',
    'June',
    'July',
    'August',
    'September',
    'October',
    'November',
    'December'
  ];

currentMonth: String;

this.currentMonth = this.months[date.getMonth()];

nextMonth() {
    this.currentMonth = ...
}

How do I go about building the nextMonth function to change the value of currentMonth? For example if its value is currently 'August', what should I add into my function to increment its value by 1, meaning, change its value to 'September'?

Upvotes: 0

Views: 40

Answers (1)

Nick
Nick

Reputation: 147146

You can use indexOf to look up currentMonth and increment:

nextMonth = months[(months.indexOf(currentMonth) + 1) % 12];

It is probably better to simply store the month number in currentMonth. Then you can simply increment currentMonth:

currentMonth = (currentMonth + 1) % 12;

and only reference the months array when you need the name:

currentMonthName = months[currentMonth];

Upvotes: 3

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