Underscore.js is a JavaScript library that provides a lot of useful functions that help in the programming in a big way like the map, filter, invoke, etc even without using any built-in objects.
The _.after() function is an inbuilt function in Underscore.js library of JavaScript which is used to create a wrapper of function which doesn’t do anything in the beginning but from the stated count it starts calling the stated function. Moreover, it is useful in a grouping of asynchronous responses, as you need to be sure if all the async calls have ended or not before preceding.
Syntax:
_.after(count, function)
Parameters: It accepts two parameters which are specified below:
- count: It is the number of counts after which the stated function will be called.
- function: It is the function stated.
Return values: This method returns the count of the function called.
Example 1:
<!DOCTYPE html> <html> <head> <script src= </script> </head> <body> <script> show = () => { console.log("neveropen") } console.log(`Show function will run for 5 times:`) // Calling after function func = _.after(3, show); func(); func(); func(); func(); func(); func(); func(); </script> </body> </html> |
Output:
Show function will run for 5 times: neveropen neveropen neveropen neveropen neveropen
Example 2:
<!DOCTYPE html> <html> <head> <script src= </script> </head> <body> <button id="button">button</button> <script> show = () => { console.log("neveropen") } // Calling after function func = _.after(3, show); let button = document.querySelector("#button"); let Run = () => { console.log(`Show function runs for 8 times:`) for (let i = 0; i < 10; i++) { func(); } } button.addEventListener("click", Run) </script> </body> </html> |
Output:
button Show function runs for 7 times: neveropen neveropen neveropen neveropen neveropen neveropen neveropen neveropen
Here, you need to click on the button in order to see the output.
Reference: https://underscorejs.org/#after
