1const single = 'Hello';
2const double = "Hello";
3const backtick = `Hello`;
4 
5// Template literals - interpolation and multi-line
6const name = "Alice";
7const greeting = `Hello, ${name}!`;          // "Hello, Alice!"
8const calc = `2 + 2 = ${2 + 2}`;             // "2 + 2 = 4"
9const multiline = `Line 1
10Line 2
11Line 3`;

1const str = "JavaScript";
2 
3console.log(str.length);    // 10
4console.log(str[0]);        // "J"
5console.log(str[4]);        // "S"
6console.log(str.at(-1));    // "t" (negative indexing with .at())
7console.log(str[100]);      // undefined
8 
9// Strings are IMMUTABLE
10str[0] = "j";              // No error, but no effect
11console.log(str);           // "JavaScript" (unchanged)

1const text = "JavaScript is awesome. JavaScript is everywhere.";
2 
3console.log(text.indexOf("JavaScript"));      // 0
4console.log(text.lastIndexOf("JavaScript"));  // 23
5console.log(text.includes("awesome"));        // true
6console.log(text.startsWith("Java"));         // true
7console.log(text.endsWith("everywhere."));    // true
8 
9// Case-insensitive search
10console.log(text.toLowerCase().includes("javascript")); // true

1const str = "Hello, World!";
2 
3// slice(start, end) - most versatile
4console.log(str.slice(0, 5));   // "Hello"
5console.log(str.slice(7));      // "World!"
6console.log(str.slice(-6));     // "orld!"
7console.log(str.slice(-6, -1)); // "orld"
8 
9// substring(start, end) - no negative indices
10console.log(str.substring(0, 5)); // "Hello"
11 
12// charAt(index)
13console.log(str.charAt(0));      // "H"
14console.log(str.charAt(100));    // "" (empty string)

1const str = "  Hello, World!  ";
2 
3// Case
4console.log(str.toUpperCase());  // "  HELLO, WORLD!  "
5console.log(str.toLowerCase());  // "  hello, world!  "
6 
7// Trimming whitespace
8console.log(str.trim());        // "Hello, World!"
9console.log(str.trimStart());   // "Hello, World!  "
10console.log(str.trimEnd());     // "  Hello, World!"
11 
12// Replacing
13const msg = "I love cats. cats are great.";
14console.log(msg.replace("cats", "dogs"));      // "I love dogs. cats are great."
15console.log(msg.replaceAll("cats", "dogs"));   // "I love dogs. dogs are great."
16 
17// Padding
18console.log("5".padStart(3, "0"));  // "005"
19console.log("5".padEnd(3, "0"));    // "500"
20console.log("42".padStart(5));      // "   42"
21 
22// Repeating
23console.log("ha".repeat(3));  // "hahaha"
24console.log("-".repeat(20));  // "--------------------"

1// Split string → array
2const csv = "apple,banana,cherry";
3const fruits = csv.split(",");
4console.log(fruits); // ["apple", "banana", "cherry"]
5 
6const words = "Hello World".split(" ");
7console.log(words); // ["Hello", "World"]
8 
9const chars = "Hello".split("");
10console.log(chars); // ["H", "e", "l", "l", "o"]
11 
12// Join array → string
13console.log(fruits.join(" | ")); // "apple | banana | cherry"
14console.log(fruits.join(""));   // "applebananacherry"

1// Strings compare lexicographically (by Unicode code points)
2console.log("a" < "b");    // true
3console.log("A" < "a");    // true (uppercase comes first)
4console.log("10" < "9");   // true! ("1" < "9" by first char)
5 
6// Case-insensitive comparison
7const a = "Hello";
8const b = "hello";
9console.log(a.toLowerCase() === b.toLowerCase()); // true
10 
11// localeCompare for proper sorting
12console.log("café".localeCompare("cafe")); // 1 (café comes after)

1// Reverse a string
2const reversed = "Hello".split("").reverse().join("");
3console.log(reversed); // "olleH"
4 
5// Capitalize first letter
6function capitalize(str) {
7return str.charAt(0).toUpperCase() + str.slice(1);
8}
9console.log(capitalize("hello")); // "Hello"
10 
11// Count occurrences
12function countChar(str, char) {
13return str.split(char).length - 1;
14}
15console.log(countChar("banana", "a")); // 3
16 
17// Truncate with ellipsis
18function truncate(str, maxLength) {
19return str.length > maxLength
20  ? str.slice(0, maxLength - 3) + "..."
21  : str;
22}
23console.log(truncate("This is a long sentence", 15)); // "This is a lo..."

1function createSlug(title) {
2return title
3  .toLowerCase()
4  .trim()
5  .replaceAll(" ", "-")
6  .replace(/[^a-z0-9-]/g, "")  // remove special chars
7  .replace(/-+/g, "-")          // collapse multiple hyphens
8  .replace(/^-|-$/g, "");       // trim leading/trailing hyphens
9}
10 
11console.log(createSlug("Hello World!"));
12// "hello-world"
13 
14console.log(createSlug("  JavaScript: The Good Parts  "));
15// "javascript-the-good-parts"
16 
17console.log(createSlug("10 Tips & Tricks for React.js"));
18// "10-tips--tricks-for-reactjs"