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 _.restArguments() function is an inbuilt function in Underscore.js library of JavaScript which is used to find a version of the function which when invoked can receive all the arguments from and beyond the stated startIndex that is collected into a single array. The number of arguments to the function would be used to determine the startIndex when a definite value is not given.
Syntax:
_.restArguments( function, startIndex )
Parameters: This method accepts two parameters as mentioned above and described below:
- function: It is the stated function.
- startIndex: It is the start position of the rest parameter. It is an optional parameter.
Return Value: This method returns a version of the function which is when invoked can receive all the arguments from and beyond the stated index.
Example 1: In this example, a user-defined function is used.
HTML
<!DOCTYPE html> <html> <head> <script src= </script> </head> <body> <script type="text/javascript"> // Calling restArguments method // with its parameter var writes = _.restArguments(function (authors, portal) { return authors + portal; }); // Calling write with its values console.log( writes( ['Nidhi1352', ' neveropen!'] ) ); </script> </body> </html> |
Output:
Nidhi1352, neveropen!
Example 2: In this example, a starting index is passed along with the user-defined function.
HTML
<!DOCTYPE html> <html> <head> <script src= </script> </head> <body> <script type="text/javascript"> // Calling restArguments method // with its parameter var writes = _.restArguments( function (authors, portal, articles) { return authors + portal + articles; }, [2]); // Calling writes with its values console.log( writes( ['Nidhi1352', ' neveropen!', ' 700 '] ) ); </script> </body> </html> |
Output:
Nidhi1352, neveropen!, 700 undefined
Example 3:
HTML
<!DOCTYPE html> <html> <head> <script src= </script> </head> <body> <script type="text/javascript"> var call = _.restArguments(function (who, whom) { return who + ' ' + _.initial(whom).join(', ') + (_.size(whom) > 2 ? ', & ' : '') + _.last(whom); }); // Calling the function above // with its values console.log( call( 'She called', 'me', 'her', 'you.' ) ); </script> </body> |
Output:
She called me, her, & you.
