With the help of _.iterators.unfoldWithReturn() method, we can get two values from iteration function where unary function is expected to return two values whenever function is invoked by using this method.
Syntax:
_.iterators.unfoldWithReturn(seed, unaryFn)
Return Value: It returns the two values from iteration function.
Note: To execute the below examples, you have to install the underscore-contrib library by using this command prompt and execute the following command.
npm install underscore-contrib
Example 1: In this example, we can see that by using _.iterators.unfoldWithReturn() method, we are able to get the values from iteration function where unary function returns two values whenever iteration function is invoked.
// Defining underscore contrib variable var _ = require( 'underscore-contrib' ); function isGFG (val) { return [val, String(val.length)]; } var geek = _.iterators.unfoldWithReturn( "Geeks" , isGFG); for ( var i = 0; i < 3; i++) { console.log(geek()); } |
Output:
Geeks [ 'Geeks', '5' ] [ [ 'Geeks', '5' ], '2' ]
Example 2:
// Defining underscore contrib variable var _ = require( 'underscore-contrib' ); function isGFG (val) { return [val + 1, val * 5]; } var geek = _.iterators.unfoldWithReturn(1, isGFG); for ( var i = 0; i < 2; i++) { console.log(geek()); } |
Output:
1 [ 2, 5 ]