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Table of contents
1.
Introduction
2.
Why This Function is Used
3.
Syntax, Parameter and Return Value
3.1.
Syntax: 
3.2.
Parameters:
3.3.
Return Value: 
4.
Examples 
4.1.
Basic Conversion to Entries:
4.2.
JavaScript
4.3.
Iterating Over Entries:
4.4.
JavaScript
4.5.
Transforming Object to Map:
4.6.
JavaScript
4.7.
Combining with Other Lodash Methods:
4.8.
JavaScript
5.
Frequently Asked Questions
5.1.
How does _.entries() differ from Object.entries() in JavaScript?
5.2.
Can _.entries() handle nested objects or arrays?
5.3.
Is _.entries() efficient for large objects?
6.
Conclusion
Last Updated: Mar 27, 2024
Easy

Lodash _.entries() Method

Author Rinki Deka
0 upvote

Introduction

Converting an object's own enumerable string keyed properties into an array of [key, value] pairs is a common task in JavaScript programming, especially when there's a need to iterate over properties or transform objects into other data structures.

Lodash _.entries() Method

Lodash's _.entries() method, which is an alias for _.toPairs(), simplifies this conversion, making the process more readable and consistent with Lodash's functional programming style.

Why This Function is Used

The _.entries() function is used to transform an object into an array of its own enumerable properties, represented as [key, value] pairs. This method is particularly useful when you need to iterate over an object's properties in a way that requires access to both the key and the value, or when transforming the object into a format that is easier to work with for certain types of operations.

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Syntax, Parameter and Return Value

Syntax: 

_.entries(object)

Parameters:

object (Object): The object to convert.

Return Value: 

(Array) - Returns the array of key-value pairs.

Examples 

Basic Conversion to Entries:

  • JavaScript

JavaScript

var _ = require('lodash');

var object = { 'a': 1, 'b': 2, 'c': 3 };

console.log(_.entries(object));

Output: 

[['a', 1], ['b', 2], ['c', 3]]


Demonstrates converting an object into an array of [key, value] pairs.

Iterating Over Entries:

  • JavaScript

JavaScript

var user = { 'name': 'John', 'age': 30, 'active': true };

_.entries(user).forEach(([key, value]) => {

 console.log(`${key}: ${value}`);

});

Output: 

'name: John', 'age: 30', 'active: true'


Shows how to iterate over an object's entries for logging or other processing.

Transforming Object to Map:

  • JavaScript

JavaScript

var settings = { 'theme': 'dark', 'layout': 'grid' };

var settingsMap = new Map(_.entries(settings));

console.log(settingsMap.get('theme'));

Output

'dark'


An example of transforming an object into a Map for easier value retrieval.

Combining with Other Lodash Methods:

  • JavaScript

JavaScript

var scores = { 'Alice': 85, 'Bob': 90, 'Clara': 88 };

var formattedScores = _.chain(scores)

 .entries()

 .map(([name, score]) => `${name}: ${score}`)

 .join(', ')

 .value();

console.log(formattedScores);

Output:

'Alice: 85, Bob: 90, Clara: 88'


Demonstrates combining _.entries() with other Lodash methods for data formatting.

Frequently Asked Questions

How does _.entries() differ from Object.entries() in JavaScript?

_.entries() is Lodash's implementation and is similar to Object.entries(). The primary difference is that Lodash methods work seamlessly with other Lodash utilities, providing consistency in a Lodash-based codebase.

Can _.entries() handle nested objects or arrays?

_.entries() will convert nested objects or arrays into entries as-is, without recursively transforming them. For nested structures, additional processing might be needed.

Is _.entries() efficient for large objects?

_.entries() is generally efficient for most use cases, but performance should be considered when dealing with very large objects or when performance is a critical factor.

Conclusion

Lodash's _.entries() method provides a straightforward and readable way to convert an object into an array of its own enumerable properties as [key, value] pairs. It's particularly useful for iterating over objects, transforming them into other data structures, and for integrating with Lodash's functional programming utilities.

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