Why do we need functions?
Doing the same thing again and again? Stop.
Say you greet three people:
console.log("Hello Riya, welcome!");
console.log("Hello Sam, welcome!");
console.log("Hello Neha, welcome!");
Same sentence, copied three times. If you later want to change "welcome" to "good morning", you must edit every single line. This is where a function saves you.
A function is a named block of code that you write once and reuse whenever you want.
How do I make one?
function greet(name) {
console.log("Hello " + name + ", welcome!");
}
function→ "I am making a reusable block".greet→ the name we give it.(name)→ an empty slot we fill in each time (this is called a parameter).
Now call it as many times as you like:
greet("Riya");
greet("Sam");
greet("Neha");
Three lines, one source of truth. Change the sentence once inside greet, and all three update together.
What is "return"?
Sometimes a function should give back an answer instead of just printing it. That is what return does.
function add(a, b) {
return a + b;
}
let total = add(5, 3); // total is now 8
console.log(total);
add hands back 8, and we store it in total. Printing is for humans to see; return is for the program to use.
Think of a function like a kitchen machine: you put ingredients in (parameters), it does the work, and hands you a finished dish back (return).