JavaScript Quick Revision 🚀

🌟 What I’ve Learned So Far in JavaScript

---

1️⃣ Basics of JavaScript 💡

• Variables: let, const, var
  • Example: const name = "Hitesh";
• Data Types: String, Number, Boolean, Object, Array, Null, Undefined, Symbol
• Operators: +, -, *, /, ===, !==, &&, ||, ++, --

---

2️⃣ Control Flow 🌉

• Conditionals: if, else, else if, switch
• Loops: for, while, do-while, for...of, for...in

---

3️⃣ Functions 📜

• Function Declaration: function greet() { ... }
• Function Expression: const greet = function() { ... };
• Arrow Functions: const greet = () => { ... };
• Default Parameters: function greet(name = "Guest") { ... }
• Higher-Order Functions: Passing functions as arguments (e.g., map, filter, reduce)

---

4️⃣ Objects & Prototypes 🛠️

• Object Literals:

  const user = {
      name: "Hitesh",
      age: 25,
      greet: function() {
          console.log("Hello!");
      },
  };

• Constructors:

  function User(name, age) {
      this.name = name;
      this.age = age;
  }

• Prototype Inheritance:

  User.prototype.sayHi = function() {
      console.log(`Hi, I am ${this.name}`);
  };

---

5️⃣ The this Keyword 🎯

• Depends on the context (e.g., global, object, function, arrow function)
• In call(), apply(), bind(), we explicitly set this.

---

6️⃣ Arrays 🎉

• Common Methods:
  • push(), pop(), shift(), unshift()
  • slice(), splice()
  • Iterators: forEach(), map(), filter(), reduce()
  • Find & Search: find(), findIndex(), indexOf()

---

7️⃣ Promises & Async Programming 🌐

• Promises:

  const promise = new Promise((resolve, reject) => {
      resolve("Success!");
  });

• Chaining: .then(), .catch()
• Async/Await:

  async function fetchData() {
      const data = await fetch(url);
      return data.json();
  }

---

8️⃣ DOM Manipulation 🌳

• Selecting Elements: document.querySelector(), getElementById()
• Modifying Elements: .innerHTML, .style, .classList
• Events: addEventListener(), Event Delegation

---

9️⃣ ES6+ Features 🌈

• Template Literals: `Hello, ${name}!`
• Destructuring:

  const { name, age } = user;
  const [first, second] = array;

• Spread & Rest: ...

  const combined = [...arr1, ...arr2];

• Modules: import, export
• Default Parameters: function greet(name = "Guest") { ... }

---

🔟 Error Handling ⚠️

• Try-Catch Block:

  try {
      riskyCode();
  } catch (error) {
      console.error(error);
  }

---

1️⃣1️⃣ Miscellaneous Tips 🎯

• Closures: Functions that remember their lexical scope.

  function outer() {
      let counter = 0;
      return function inner() {
          counter++;
          console.log(counter);
      };
  }

• Event Loop: Understanding how JavaScript handles asynchronous tasks using the Call Stack, Web APIs, and Event Queue.
• Hoisting: Variable and function declarations are moved to the top of the scope.

---

🌟 Next Steps

• Master advanced concepts like Modules, Web APIs, and Design Patterns. 🚀

---

💪 Keep Learning and Coding! 💻

---