Case-Insensitive Substring Search in JavaScript

Introduction

In this lab, we will be exploring how to perform a case-insensitive substring search in JavaScript. We will use the RegExp constructor and the 'i' flag to create a regular expression that can match the given search string, ignoring the case. By the end of this lab, you will have a better understanding of how to search for substrings without having to worry about case-sensitivity.

Skills Graph

%%%%{init: {'theme':'neutral'}}%%%% flowchart RL javascript(("JavaScript")) -.-> javascript/BasicConceptsGroup(["Basic Concepts"]) javascript/BasicConceptsGroup -.-> javascript/variables("Variables") javascript/BasicConceptsGroup -.-> javascript/data_types("Data Types") javascript/BasicConceptsGroup -.-> javascript/arith_ops("Arithmetic Operators") javascript/BasicConceptsGroup -.-> javascript/comp_ops("Comparison Operators") subgraph Lab Skills javascript/variables -.-> lab-28386{{"Case-Insensitive Substring Search"}} javascript/data_types -.-> lab-28386{{"Case-Insensitive Substring Search"}} javascript/arith_ops -.-> lab-28386{{"Case-Insensitive Substring Search"}} javascript/comp_ops -.-> lab-28386{{"Case-Insensitive Substring Search"}} end

Case-Insensitive Substring Search

To check if a string contains a substring regardless of the case, follow these steps:

Use the RegExp constructor with the 'i' flag to create a regular expression that matches the given searchString, ignoring the case.
Use RegExp.prototype.test() to check if the string contains the substring.

Here is an example code snippet:

const includesCaseInsensitive = (str, searchString) =>
  new RegExp(searchString, "i").test(str);

To test this function, you can run:

includesCaseInsensitive("Blue Whale", "blue"); // true

Summary

Congratulations! You have completed the Case-Insensitive Substring Search lab. You can practice more labs in LabEx to improve your skills.