Javascript Get Yesterdays Day of Week
Try
let yesterday = {
'Monday': 'Sunday',
'Tuesday': 'Monday',
'Wednesday': 'Tuesday',
'Thursday': 'Wednesday',
'Friday': 'Thursday',
'Saturday': 'Friday',
'Sunday': 'Saturday',
}
console.log(yesterday['Monday']);One straightforward approach, assuming correct input, would be using arrays:
days = ['Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday'];
previousDay = days[(days.indexOf(currentDay)-1+7)%7];
You can use indexOf and return Sun when you exceed array range:
let currentDay = "Mon";
let days = ["Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"];
let prevDay = days[days.indexOf(currentDay) - 1 ] || "Sun";
console.log(prevDay);