How to Do Case Insensitive String Comparison?

When working with strings in JavaScript, you may come across situations where you need to compare strings in a case-insensitive manner. By default, JavaScript’s string comparison is case-sensitive, meaning that “hello” and “Hello” would be considered different strings.

Fortunately, there are several ways to perform case-insensitive string comparison in JavaScript. Let’s explore a few of them:

Method 1: Using the toLowerCase() method

One way to achieve case-insensitive string comparison is by converting both strings to lowercase using the toLowerCase() method and then comparing them. This method ensures that the comparison is not affected by the case of the letters.

// Case-insensitive string comparison using toLowerCase()
const string1 = "hello";
const string2 = "Hello";

if (string1.toLowerCase() === string2.toLowerCase()) {
  console.log("Strings are equal (case-insensitive)");
} else {
  console.log("Strings are not equal (case-insensitive)");
}

Output: Strings are equal (case-insensitive)

Method 2: Using the localeCompare() method

The localeCompare() method is another approach to perform case-insensitive string comparison. It compares two strings and returns a number indicating their relative order. By passing the "en" argument to the method, we can ensure that the comparison is case-insensitive.

// Case-insensitive string comparison using localeCompare()
const string1 = "hello";
const string2 = "Hello";

if (string1.localeCompare(string2, "en", { sensitivity: "base" }) === 0) {
  console.log("Strings are equal (case-insensitive)");
} else {
  console.log("Strings are not equal (case-insensitive)");
}

Output: Strings are equal (case-insensitive)

Method 3: Using regular expressions

Regular expressions can also be used for case-insensitive string comparison. By using the i flag in the regular expression pattern, we can make the comparison case-insensitive.

// Case-insensitive string comparison using regular expressions
const string1 = "hello";
const string2 = "Hello";

const regex = new RegExp(string1, "i");

if (regex.test(string2)) {
  console.log("Strings are equal (case-insensitive)");
} else {
  console.log("Strings are not equal (case-insensitive)");
}

Output: Strings are equal (case-insensitive)

These are just a few ways to perform case-insensitive string comparison in JavaScript. Choose the method that best suits your needs and implement it in your code to ensure accurate string comparisons.