Lodash _.prototype.next() Method

Lodash is a JavaScript library that works on the top of underscore.js. Lodash helps in working with arrays, strings, objects, numbers, etc.

The _.prototype.next() method of Sequence in lodash is used to find the next value on a wrapped object which follows the iterator protocol.

Syntax:

_.prototype.next()

Parameters: This method doesn’t accept any parameter.

Return Value: This method returns the value of next iterator.

Example 1:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Initializing wrapped value
var wrapper = _([5, 6]);

// Calling prototype.next() method
let res1 = wrapper.next();
let res2 = wrapper.next();

// Displays output
console.log(res1);
console.log(res2);

Output:

{ done: false, value: 5 }
{ done: false, value: 6 }

Example 2:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Initializing wrapped value
var wrapper = _([]);

// Calling prototype.next() method
let result = wrapper.next();

// Displays output
console.log(result);

Output:

{ done: true, value: undefined }

Here, the output is ‘undefined’ as there is no value to print.

Example 3:

Javascript

// Requiring lodash library
const _ = require('lodash');

// Calling prototype.next() method
let result1 = _({'f':5}).next();
let result2 = _({'g':(1/0)}).next();

// Displays output
console.log(result1);
console.log(result2);

Output:

{ done: false, value: 5 }
{ done: false, value: Infinity }

Here, only the defined value is returned to the output.

Reference: https://lodash.com/docs/4.17.15#prototype-next