Syntax, Parameter, and Return Value
Syntax:
_.dropRightWhile(array, [predicate=_.identity])
Parameters:
-
array (Array): The array to process.
- predicate (Function): The function invoked per iteration.
Return Value:
Returns the slice of array.
Examples with Proper Codes
Example 1: Using an Object Predicate
JavaScript
const _ = require('lodash');
const users = [
{ 'user': 'barney', 'active': false },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': true }
];
const result = _.dropRightWhile(users, function(o) { return !o.active; });
console.log(result);
You can also try this code with Online Javascript Compiler
Output:
[{ 'user': 'barney', 'active': false }]
Drops elements from the end as long as they are not active.
Example 2: Using Arrow Function
JavaScript
const numbers = [1, 2, 3, 4, 5, 6];
const result = _.dropRightWhile(numbers, n => n > 4);
console.log(result);
You can also try this code with Online Javascript Compiler
Output:
[1, 2, 3, 4]
Drops numbers greater than 4 from the end of the array.
Example 3: Property Shorthand
JavaScript
const users = [
{ 'user': 'barney', 'active': true },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': false }
];
const result = _.dropRightWhile(users, {'user': 'pebbles', 'active': false});
console.log(result);
You can also try this code with Online Javascript Compiler
Output:
[{ 'user': 'barney', 'active': true }, { 'user': 'fred', 'active': false }]
Uses an object to specify the predicate.
Example 4: Property Name Shorthand
JavaScript
const users = [
{ 'user': 'barney', 'active': true },
{ 'user': 'fred', 'active': false },
{ 'user': 'pebbles', 'active': true }
];
const result = _.dropRightWhile(users, 'active');
console.log(result);
You can also try this code with Online Javascript Compiler
Output:
[{ 'user': 'barney', 'active': true }, { 'user': 'fred', 'active': false }]
Drops users from the end as long as the 'active' property is true.
Frequently Asked Questions
What is the difference between _.dropWhile() and _.dropRightWhile()?
_.dropWhile() removes elements from the beginning of the array based on a predicate, whereas _.dropRightWhile() does so from the end.
Can _.dropRightWhile() handle complex predicates?
Yes, it can handle complex predicates, including those evaluating object properties or performing more intricate checks.
How does Lodash ensure efficiency in _.dropRightWhile()?
Lodash optimizes _.dropRightWhile() for performance, particularly in scenarios involving large arrays or complex predicates.
Conclusion
The _.dropRightWhile() method in Lodash is a versatile and powerful tool for array manipulation based on conditions. Its ability to dynamically trim arrays from the end, based on a predicate function, makes it an essential method for developers handling complex data structures and conditions. This method simplifies array processing tasks, allowing for more efficient and readable code in JavaScript applications.
You can refer to our guided paths on the Coding Ninjas. You can check our course to learn more about DSA, DBMS, Competitive Programming, Python, Java, JavaScript, etc.
Also, check out some of the Guided Paths on topics such as Data Structure and Algorithms, Competitive Programming, Operating Systems, Computer Networks, DBMS, System Design, etc., as well as some Contests, Test Series, and Interview Experiences curated by top Industry Experts.
84+ registered 