Lodash _.includes() Method

Syntax, Parameter and Return Value

Syntax:

 _.includes(collection, value, [fromIndex=0])

Parameters:

• collection (Array|Object|string): The collection to search.
   
• value: The value to search for.
   
• [fromIndex=0] (number): The index to start the search from.

Return Value: 

(boolean) - Returns true if value is found, else false.

Examples 

Checking for a Number in an Array:

• JavaScript

JavaScript

var _ = require('lodash');

var numbers = [1, 2, 3, 4, 5];

var includesTwo = _.includes(numbers, 2);

console.log(includesTwo); 

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 Output: 

true

Demonstrates searching for a number in an array.

Searching for a Property Value in an Object:

• JavaScript

JavaScript

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

var includesThree = _.includes(object, 3);

console.log(includesThree); 

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 Output: 

true

Shows how to search for a value within an object's properties.

Finding a Substring in a String:

• JavaScript

JavaScript

var string = "hello world";

var includesHello = _.includes(string, "hello");

console.log(includesHello); 

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 Output: 

true

An example of checking for a substring within a string.

Using fromIndex for Array Search:

• JavaScript

JavaScript

var includesTwoAfterIndexTwo = _.includes(numbers, 2, 2);

console.log(includesTwoAfterIndexTwo); 

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Output:

 false

Demonstrates searching for an element in an array starting from a specific index.

Frequently Asked Questions 

How does _.includes() differ from native JavaScript includes?

Lodash's _.includes() works across different types of collections, including arrays, objects, and strings, unlike the native includes which is limited to arrays and strings.

Can _.includes() be used to find partial objects in an array?

_.includes() checks for primitive values and will not match partial objects; it compares object references for equality.

Is _.includes() case-sensitive when searching in strings?

Yes, when searching within strings, _.includes() is case-sensitive and will only find exact matches.

Conclusion

Lodash's _.includes() method is a versatile and efficient way to check for the presence of a value within various types of collections. It simplifies the process of searching and validating data, enhancing the functionality and readability of JavaScript code.

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