JavaScript: Functions

Yap Yee Qiang's photo
Yap Yee Qiang
·May 8, 2022·

1 min read

Table of contents

  • What is a function?
  • Creating a function
  • Using a function
  • Function parameters

What is a function?

Functions are JavaScript codes that can:

  1. Saved for later use. You can call it anytime you want.
  2. Use it multiple times. Not like loops, you can control when and where to use functions.



Creating a function

You create a function by using the keyword function.

In more advanced sections, we will look into other ways of creating functions.

function name() {
    // your code
}



Using a function

Let's say we have a sayHello function.

Use the function by calling the name followed by a ().

function sayHello() {
    console.log('Hello');
}

sayHello(); // <- here



Function parameters

What if you want to say hello to specific names?

We can use parameters to customize our how the task is run.

function sayHello(name) {
    console.log(`Hello ${name}`);
}

sayHello('A'); // output: Hello A
sayHello('B'); // output: Hello B
sayHello('C'); // output: Hello C
 
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