With the help of _.iterators.mapcat() method, we can get the function iterator which when called return the value which is flattening the contents of iterator and combined with the unary function by using this method.
Syntax:
_.iterators.mapcat(iter, unaryFn)
Parameters: This method accepts two parameter as mentioned above and described below:
- iter: This parameter holds the iterator list of the array.
- unaryFn: This parameter holds the unary function key.
Return value: Return the function iterator which generate the value by mapping with unaryFn.
Note: To execute the below examples, you have to install the underscore-contrib library by using this command prompt we have to execute the following command.
npm install underscore-contrib
Below example illustrate the Underscore.js _.iterators.mapcat() method in JavaScript:
Example 1: In this example, we can see that by using _.iterators.mapcat() method, we are able to get the function iterator which can generate the value after mapping with the unary function by using this method.
Javascript
// Defining underscore contrib variable var _ = require('underscore-contrib');function generateNumber (x) { return _.iterators.List(_.range(1, x));}var treeIter = _.iterators.Tree([2, [3]]);var geek = _.iterators.mapcat(treeIter, generateNumber);geek();geek();geek(); |
Output :
1 1 2
Example 2:
Javascript
// Defining underscore contrib variable var _ = require('underscore-contrib');function generateNumber (x) { return _.iterators.List(_.range(x));}var treeIter = _.iterators.Tree([[2, 1], [1, 3]]);var geek = _.iterators.mapcat(treeIter, generateNumber);for(var i = 0; i < 5; i++) { console.log(geek());} |
Output:
0 1 0 0 0
