The setHours function in JS is a method of the Date class with the following syntax:
setHours(hoursValue)
setHours(hoursValue, minutesValue)
setHours(hoursValue, minutesValue, secondsValue)
setHours(hoursValue, minutesValue, secondsValue, msValue)
hoursValue is an integer value from 0 to 23 (representing time in 24-hour clock format). A value greater than 23 is added as extra hours to the date object.minutesValue is an integer value from 0 to 59 that represents minutes. A value greater than 59 is added as extra minutes to the date object.secondsValue is an integer value from 0 to 59 that represents seconds. A value greater than 59 is added as extra seconds to the date object.msValue is an integer value from 0 to 999 that represents milliseconds. A value greater than 999 is added as extra milliseconds to the date object.Note: Only the
hoursValueparameter is required, the rest are optional.
setHours returns the number of milliseconds elapsed since 1 January 1970 00:00:00 UTC till the updated time.The setHours function is called on a Date object, which results in the specified parameters being changed in the Date object.
The following code demonstrates the usage of the setHours function:
let d1 = new Date('June 29, 2021 15:39:05:32');let d2 = new Date('June 29, 2021 15:39:05:32');let d3 = new Date('June 29, 2021 15:39:05:32');let d4 = new Date('June 29, 2021 15:39:05:32');console.log('Dates Before Changing:');console.log('d1: ', d1);console.log('d2: ', d2);console.log('d3: ', d3);console.log('d4: ', d4);d1.setHours(8);d2.setHours(8, 8);d3.setHours(8, 8, 8);d4.setHours(8, 8, 8, 8);console.log('Dates After Changing:');console.log('d1: ', d1);console.log('d2: ', d2);console.log('d3: ', d3);console.log('d4: ', d4);
In the example above, the variables d1, d2, d3, and d4 are Date objects that have the same date, June 29, 2021 15:39:05:32, initially. The setHours function is applied on all of them to make the hours, minutes, seconds, and milliseconds to the value 8. For d1, only the hours is set to 8. For d2, both hours and minutes are set to 8. For d3, hours, minutes, and seconds are set to 8. Finally, for d4, hours, minutes, seconds, and milliseconds are set to 8.
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