/**
* TypeScript String Example
* -------------------------
* Demonstrates:
* - Creating strings
* - Common string methods
* - String searching
* - String manipulation
* - Template literals
* - Custom functions
* - Type annotations
*/
/*
Common operations include
-------------------------
trim()
toUpperCase()
toLowerCase()
includes()
startsWith()
endsWith()
slice()
replace()
split()
repeat()
*/
"use strict";
/**
* Converts text to Title Case.
*
* Example:
* "hello world" -> "Hello World"
*
* @param text Input string
* @returns Title-cased string
*/
function toTitleCase(text: string): string {
return text
.toLowerCase()
.split(" ")
.map((word: string): string => {
if (word.length === 0) {
return "";
}
return (
word.charAt(0).toUpperCase() +
word.slice(1)
);
})
.join(" ");
}
/**
* Counts the number of words in a string.
*
* @param text Input string
* @returns Number of words
*/
function countWords(text: string): number {
return text
.trim()
.split(/\s+/)
.filter((word: string): boolean => word.length > 0)
.length;
}
/**
* Reverses a string.
*
* @param text Input string
* @returns Reversed string
*/
function reverseString(text: string): string {
return text.split("").reverse().join("");
}
// ----------------------------------------------------
// Create a string
// ----------------------------------------------------
const message: string = " Hello TypeScript World! ";
console.log("=== Original String ===");
console.log(message);
// ----------------------------------------------------
// Trim whitespace
// ----------------------------------------------------
const trimmedMessage: string = message.trim();
console.log("\n=== trim() ===");
console.log(trimmedMessage);
// ----------------------------------------------------
// Length
// ----------------------------------------------------
const length: number = trimmedMessage.length;
console.log("\n=== length ===");
console.log(length);
// ----------------------------------------------------
// Character Access
// ----------------------------------------------------
console.log("\n=== Character Access ===");
const firstCharacter: string = trimmedMessage[0];
const secondCharacter: string = trimmedMessage.charAt(1);
console.log(firstCharacter);
console.log(secondCharacter);
// ----------------------------------------------------
// Case Conversion
// ----------------------------------------------------
console.log("\n=== Case Conversion ===");
const uppercase: string =
trimmedMessage.toUpperCase();
const lowercase: string =
trimmedMessage.toLowerCase();
console.log(uppercase);
console.log(lowercase);
// ----------------------------------------------------
// Search Methods
// ----------------------------------------------------
console.log("\n=== Search Methods ===");
const containsTypeScript: boolean =
trimmedMessage.includes("TypeScript");
const startsWithHello: boolean =
trimmedMessage.startsWith("Hello");
const endsWithWorld: boolean =
trimmedMessage.endsWith("World!");
console.log(containsTypeScript);
console.log(startsWithHello);
console.log(endsWithWorld);
// ----------------------------------------------------
// indexOf()
// ----------------------------------------------------
const position: number =
trimmedMessage.indexOf("TypeScript");
console.log("\n=== indexOf() ===");
console.log(position);
// ----------------------------------------------------
// Extract Text
// ----------------------------------------------------
console.log("\n=== slice() ===");
const extractedText: string =
trimmedMessage.slice(6, 16);
console.log(extractedText);
// ----------------------------------------------------
// Replace Text
// ----------------------------------------------------
console.log("\n=== replace() ===");
const updatedMessage: string =
trimmedMessage.replace(
"TypeScript",
"JavaScript"
);
console.log(updatedMessage);
// ----------------------------------------------------
// Split Text
// ----------------------------------------------------
console.log("\n=== split() ===");
const words: string[] =
trimmedMessage.split(" ");
console.log(words);
// ----------------------------------------------------
// Repeat Text
// ----------------------------------------------------
console.log("\n=== repeat() ===");
const separator: string = "-".repeat(25);
console.log(separator);
// ----------------------------------------------------
// Template Literals
// ----------------------------------------------------
console.log("\n=== Template Literals ===");
const language: string = "TypeScript";
const version: string = "5.x";
const description: string =
`${language} Version ${version}`;
console.log(description);
// ----------------------------------------------------
// Custom Function Examples
// ----------------------------------------------------
console.log("\n=== Custom Functions ===");
const titleCaseText: string =
toTitleCase("learning typescript is fun");
const wordCount: number =
countWords(trimmedMessage);
const reversedText: string =
reverseString(trimmedMessage);
console.log("Title Case:", titleCaseText);
console.log("Word Count:", wordCount);
console.log("Reversed :", reversedText);
/*
run:
=== Original String ===
Hello TypeScript World!
=== trim() ===
Hello TypeScript World!
=== length ===
23
=== Character Access ===
H
e
=== Case Conversion ===
HELLO TYPESCRIPT WORLD!
hello typescript world!
=== Search Methods ===
true
true
true
=== indexOf() ===
6
=== slice() ===
TypeScript
=== replace() ===
Hello JavaScript World!
=== split() ===
[ 'Hello', 'TypeScript', 'World!' ]
=== repeat() ===
-------------------------
=== Template Literals ===
TypeScript Version 5.x
=== Custom Functions ===
Title Case: Learning Typescript Is Fun
Word Count: 3
Reversed : !dlroW tpircSepyT olleH
*/
