TypeScript String toLowerCase()

In this chapter, we will explore the toLowerCase() method in TypeScript. This method is a built-in function that helps in converting all the characters in a string to lowercase. Understanding how to use toLowerCase() is useful for standardizing string cases and performing case-insensitive comparisons.

Table of Contents

1. Definition
2. Syntax
3. Examples
4. Conclusion

1. Definition

The toLowerCase() method returns the calling string value converted to lowercase. This method does not affect the original string but returns a new string with all lowercase characters.

2. Syntax

string.toLowerCase();

Parameters

The toLowerCase() method does not take any parameters.

Return Value

The method returns a new string representing the calling string converted to lowercase.

3. Examples

Let's look at some examples to understand how toLowerCase() works in TypeScript.

Example 1: Basic Usage

In this example, we convert a string to lowercase.

let str: string = "Hello, TypeScript!";
let result = str.toLowerCase();
console.log(result); // Output: hello, typescript!

Example 2: Mixed Case String

In this example, we convert a string with mixed case characters to lowercase.

let str: string = "TypeScript Is Awesome!";
let result = str.toLowerCase();
console.log(result); // Output: typescript is awesome!

Example 3: String with Numbers and Symbols

In this example, we convert a string containing numbers and symbols to lowercase. Note that numbers and symbols are unaffected by the toLowerCase() method.

let str: string = "123 ABC! @#";
let result = str.toLowerCase();
console.log(result); // Output: 123 abc! @#

Example 4: Using toLowerCase() for Case-Insensitive Comparison

In this example, we use toLowerCase() to perform a case-insensitive comparison between two strings.

let str1: string = "TypeScript";
let str2: string = "typescript";

if (str1.toLowerCase() === str2.toLowerCase()) {
  console.log("The strings are equal (case-insensitive).");
} else {
  console.log("The strings are not equal.");
}
// Output: The strings are equal (case-insensitive).

4. Conclusion

In this chapter, we explored the toLowerCase() method in TypeScript, which is used to convert all the characters in a string to lowercase. We covered its definition, syntax, parameters, return value, and provided several examples to demonstrate its usage. Understanding how to use toLowerCase() effectively can help in various string manipulation tasks in TypeScript, especially when standardizing string cases and performing case-insensitive comparisons.