Practice Questions — Strings and Template Literals

function titleCase(str) {
  return str.split(" ")
    .map(word => word.charAt(0).toUpperCase() + word.slice(1))
    .join(" ");
}

console.log(titleCase("hello world from javascript"));

const str = "programming";
const freq = str.split("").reduce((acc, char) => {
  acc[char] = (acc[char] || 0) + 1;
  return acc;
}, {});

console.log(freq);

const student = {
  name: "Kavya",
  grade: "10th",
  score: 94,
  subjects: ["Maths", "Science", "English"]
};

const card = `<div class="student-card">
  <h3>${student.name}</h3>
  <p>Grade: ${student.grade} | Score: ${student.score}/100</p>
  <p>Status: ${student.score >= 90 ? "Distinction" : "Pass"}</p>
  <h4>Subjects:</h4>
  <ul>
    ${student.subjects.map(s => `<li>${s}</li>`).join("\n    ")}
  </ul>
</div>`;

console.log(card);

function isPalindrome(str) {
  const clean = str.toLowerCase().replaceAll(" ", "");
  const reversed = clean.split("").reverse().join("");
  return clean === reversed;
}

console.log(isPalindrome("Race Car"));   // true
console.log(isPalindrome("Hello"));      // false
console.log(isPalindrome("Was It A Car Or A Cat I Saw")); // true

function isValidEmail(email) {
  const trimmed = email.trim();
  const atIndex = trimmed.indexOf("@");
  
  if (atIndex < 1) return false; // nothing before @
  if (trimmed.lastIndexOf("@") !== atIndex) return false; // multiple @
  
  const domain = trimmed.slice(atIndex + 1);
  if (!domain.includes(".")) return false; // no dot in domain
  if (domain.startsWith(".") || domain.endsWith(".")) return false;
  
  return true;
}

console.log(isValidEmail("diya@school.com"));  // true
console.log(isValidEmail("@school.com"));      // false
console.log(isValidEmail("diya@school"));      // false
console.log(isValidEmail("diya@@school.com")); // false

function compress(str) {
  if (str.length === 0) return "";
  
  let result = "";
  let count = 1;
  
  for (let i = 1; i <= str.length; i++) {
    if (i < str.length && str[i] === str[i - 1]) {
      count++;
    } else {
      result += str[i - 1] + count;
      count = 1;
    }
  }
  
  return result;
}

console.log(compress("aaabbbccda"));  // a3b3c2d1a1
console.log(compress("aabbcc"));      // a2b2c2
console.log(compress("abcdef"));      // a1b1c1d1e1f1

const students = [
  { name: "Aarav", maths: 95, science: 88 },
  { name: "Priya", maths: 78, science: 92 },
  { name: "Rohan", maths: 85, science: 76 }
];

const header = "Name".padEnd(12) + "Maths".padStart(8) + "Science".padStart(10);
const separator = "-".repeat(30);
const rows = students.map(s => 
  s.name.padEnd(12) + String(s.maths).padStart(8) + String(s.science).padStart(10)
);

console.log(header);
console.log(separator);
rows.forEach(row => console.log(row));

function slugify(title) {
  return title
    .toLowerCase()
    .trim()
    .replace(/[^a-z0-9\s-]/g, "")  // remove special chars
    .replace(/\s+/g, "-")           // spaces to hyphens
    .replace(/-+/g, "-")            // collapse multiple hyphens
    .replace(/^-|-$/g, "");          // trim hyphens
}

console.log(slugify("Hello World! This is Great"));
console.log(slugify("  JavaScript: The Good Parts  "));
console.log(slugify("10 Tips & Tricks for Coding!"));