00-declaration-function.md

title	theme	transition	highlightTheme	slideNumber	enableMenu	enableChalkboard	autoSlide
Functions	night	slide	dracula	true	false	false	0

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Chapter Overview

This chapter should cover the following:

1. Anatomy of functions
2. Catagories of Functions
3. Simple Example of Each function
   • Links to subjections for detailed breakdown of each

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What is Function?

A block of reusable code.

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Function Declaration

What a function declaration looks like:

function add(param1, param2){
  return param1 + param2;
};
add(1, 2) //return a value of 3

Has the following Features:

Block Syntax, with {} at the begining and the end of the function and usually followed by a ; {.fragment .current-only data-code-focus=1-3}

:::block

• Function keyword
• Name of function, add
• Parameters (param1, param2), which act as variables inside the functions definition. {.fragment .current-only data-code-focus=1-1} :::

Return keyword, ends the function and the result is returned {.fragment .current-only data-code-focus=2-2}

:::block

• Calling the Function

• When the function is called, we pass values into the arguements (1,2) {.fragment .current-only data-code-focus=4-4}

• When the function is called, we pass values into the arguements (1,2) {.fragment .current-only data-code-focus=1-2}

Function Declaration

function functionDeclaration(params) {
   console.log(`hello ${params} \n`);
}
functionDeclaration("hello");
console.log(global) // not hoisted in node.js 
// console.log(window.functionDeclaration("hello")) 

Remember function declarations is hoisted in the browser but not in node in{.fragment .current-only data-code-focus=5-6}

This errors out declarations is hoisted in the browser but not in node in{.fragment .current-only data-code-focus=5-5}

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