Trusted answers to developer questions
Trusted Answers to Developer Questions

Related Tags

lodash
communitycreator
index

What is the _.indexOf() method in Lodash?

Shubham Singh Kshatriya

Grokking Modern System Design Interview for Engineers & Managers

Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.

Overview

The _.indexOf() method in Lodash is used to get the index of the first occurrence of a value from an array.

Syntax

_.indexOf(array, value, startIndex)
Syntax of the _.indexOf() method

Parameters

This method accepts the following parameters:

  • array: This is the array to be queried.
  • value: This is the value to be searched.
  • startIndex: This is the index from where the search starts. If not specified, it will take 0 as default. If negative, it will serve as an offset from the end of the array.

Return value

This method returns the index of the value if found. Otherwise, it returns -1.

Example

Let’s look at an example of the _.indexOf() method in the code snippet below:

Console
Implementation of the _.indexOf() method

Explanation

In the HTML tab:

  • Line 5: We import the lodash script.

In the JavaScript tab:

  • Line 2: We create an array numbers and populate it with a few values.
  • Line 5: We declare a variable value and initialize it with 3.
  • Line 8: We use the _.indexOf() method to find the index of the value.
  • Line 11: We print the index to the console.

Output

In the output, we see 2, which is the index of the value 3 in the array numbers.

RELATED TAGS

lodash
communitycreator
index

CONTRIBUTOR

Shubham Singh Kshatriya

Grokking Modern System Design Interview for Engineers & Managers

Ace your System Design Interview and take your career to the next level. Learn to handle the design of applications like Netflix, Quora, Facebook, Uber, and many more in a 45-min interview. Learn the RESHADED framework for architecting web-scale applications by determining requirements, constraints, and assumptions before diving into a step-by-step design process.

Keep Exploring