The following approach covers how to find the 3 letters of the string, here we will use the day’s name as a string by using JavaScript for a given date.
These are the approaches by which we can get the first three characters of a string using JavaScript:
- Using Slice() method
- Using string.substr() method
Example:
Input: today
Output: SUN
Input: tomorrow
Output: MON
Input: yesterday
Output: SAT
Input: 01-04-2021
Output: THU
Approach 1: Using Slice() method
- First, get the current date using the new Date( ) and store it in a variable (date).
- If the input date is tomorrow the using setDate() method increases one date to the Date(), if the input date is yesterday the decrease one date from the Date().
- And if the value is not today then we pass the input date to the Date() object. That’s why if the user inputs today then the Date() will be the default and the default Date() object depicts today’s Date().
- Now by using the date.getDay() method we get the day of the date. It will return a number ranging from 0-6 where 0 represents Sunday and 6 represents Saturday and the remaining days lie in order. Create an array containing the days of the week. By using the index get the preferred day name.
- By using the slice method extract the Beginning three characters.
Example: This example shows the first three letters of the current day.
Javascript
// Javascript program to get three beginning characters of the day function getDay(d) { let date = new Date(); let days = [ "SUNDAY" , "MONDAY" , "TUESDAY" , "WEDNESDAY" , "THURSDAY" , "FRIDAY" , "SATURDAY" ] if (d === "tomorrow" ) { date.setDate(date.getDate() + 1) } else if (d === "yesterday" ) { date.setDate(date.getDate() - 1) } else if (d != "today" ) { date = new Date(d); } // Get the todays day let day = days[date.getDay()] // Extract three characters from the beginning let threeCharDay = day.slice(0, 3) // Print or return the three character day console.log(threeCharDay) } // Function calls getDay( "yesterday" ) getDay( "today" ) getDay( "tomorrow" ) getDay( "2021-03-30" ) getDay( "2021-03-31" ) getDay( "2021-04-01" ) |
SUN MON TUE TUE WED THU
Approach 2: Using string.substr() method:
Syntax:
let temp = str.substr(0, 3);
Example: This example shows the first three letters of the current day using string.substr() method.
Javascript
// Javascript program to get three beginning characters of the day function getDay(d) { let date = new Date(); let days = [ "SUNDAY" , "MONDAY" , "TUESDAY" , "WEDNESDAY" , "THURSDAY" , "FRIDAY" , "SATURDAY" ] if (d === "tomorrow" ) { date.setDate(date.getDate() + 1) } else if (d === "yesterday" ) { date.setDate(date.getDate() - 1) } else if (d != "today" ) { date = new Date(d); } // Get the todays day let day = days[date.getDay()] // Extract three characters from the beginning let threeCharDay = day.substr(0, 3) // Print or return the three character day console.log(threeCharDay) } // Function calls getDay( "yesterday" ) getDay( "today" ) getDay( "tomorrow" ) getDay( "2021-03-30" ) getDay( "2021-03-31" ) getDay( "2021-04-01" ) |
SUN MON TUE TUE WED THU