Q214- What is the difference between call, apply, and bind?

All three methods — call(), apply(), and bind() — are used to manually set the value of this inside a function.
They differ mainly in how arguments are passed and when the function is executed.

---

1️⃣ call()

• Invokes the function immediately.
• Passes arguments individually (comma-separated).

function greet(city, country) {
  console.log(`Hello ${this.name} from ${city}, ${country}`);
}

const user = { name: "Teekam" };

greet.call(user, "Jaipur", "India");
// Output: Hello Teekam from Jaipur, India

✅ call() → call now, pass arguments one by one.

---

2️⃣ apply()

• Also invokes immediately, just like call().
• But it expects arguments as an array.

greet.apply(user, ["Jaipur", "India"]);
// Output: Hello Teekam from Jaipur, India

✅ apply() → call now, pass arguments as an array.

---

3️⃣ bind()

• Does not invoke immediately.
• Returns a new function with this permanently bound.
• You can call it later.

const greetUser = greet.bind(user, "Jaipur", "India");
greetUser(); 
// Output: Hello Teekam from Jaipur, India

✅ bind() → bind now, call later.

---

🔹 Summary Table

Method	Executes Immediately?	How to Pass Arguments	Returns What?	Use Case
call()	✅ Yes	Comma-separated	Function result	Simple function call
apply()	✅ Yes	Array	Function result	Use when args are in an array
bind()	❌ No	Comma-separated	New function	Use for callbacks or event handlers

---

💡 In Short:

• call() → call function immediately with arguments listed.
• apply() → call function immediately with arguments in an array.
• bind() → return a new function with fixed this, call later.