How do I subtract one week from this date in JavaScript?

To subtract one week (7 days) from a date in JavaScript, use the setDate() method combined with getDate() to modify the date object directly.

Syntax

var newDate = new Date(currentDate.setDate(currentDate.getDate() - 7));

Method 1: Modifying Current Date

First, get the current date, then subtract 7 days using setDate():

var currentDate = new Date();
console.log("The current Date = " + currentDate);

var before7Daysdate = new Date(currentDate.setDate(currentDate.getDate() - 7));
console.log("The One week ago date = " + before7Daysdate);

The current Date = Tue Jul 14 2020 19:12:43 GMT+0530 (India Standard Time)
The One week ago date = Tue Jul 07 2020 19:12:43 GMT+0530 (India Standard Time)

Method 2: Without Modifying Original Date

To keep the original date unchanged, create a new Date object:

var currentDate = new Date();
console.log("Original date = " + currentDate);

var oneWeekAgo = new Date(currentDate);
oneWeekAgo.setDate(currentDate.getDate() - 7);
console.log("One week ago = " + oneWeekAgo);
console.log("Original unchanged = " + currentDate);

Original date = Tue Jul 14 2020 19:12:43 GMT+0530 (India Standard Time)
One week ago = Tue Jul 07 2020 19:12:43 GMT+0530 (India Standard Time)
Original unchanged = Tue Jul 14 2020 19:12:43 GMT+0530 (India Standard Time)

Method 3: Using Milliseconds

Alternatively, subtract 7 days worth of milliseconds:

var currentDate = new Date();
var millisecondsInWeek = 7 * 24 * 60 * 60 * 1000; // 7 days in milliseconds
var oneWeekAgo = new Date(currentDate.getTime() - millisecondsInWeek);

console.log("Current date = " + currentDate);
console.log("One week ago = " + oneWeekAgo);

Current date = Tue Jul 14 2020 19:12:43 GMT+0530 (India Standard Time)
One week ago = Tue Jul 07 2020 19:12:43 GMT+0530 (India Standard Time)

Comparison

Conclusion

Use setDate(getDate() - 7) for simplicity. Create a new Date object first if you need to preserve the original date. The milliseconds approach offers more precision for complex date calculations.