Kate’s Journal

Definition Recursion is a programming concept, which happens when a function calls itself. It is used in a mathematical problem solving and a logical solution.

function sayHeeya() {
      console.log("Hi heeya");
      sayHeeya();
}
sayHeeya();

function sayHeeya(count) {
if (count == 0){
   return;
}
console.log("Hi heeya");
   sayHeeya(count - 1);
}
sayHeeya(10);

Each one of the functions copies will have a new set of internal variables called a stack. Now without a base case JavaScript will continue to ask for new variables until it either runs out of memory or the browser runs into an internal limit. Now when the computer runs out of memory that’s called a stack overflow. (Villalobos)

function twoToThePowerOf(number) {
	if (number == 0) {
		return 1;
	} else {
		return 2 * twoToThePowerOf(number - 1);
	}
}
console.log(twoToThePowerOf(2));

2 ^ 5 = 2 * (2 ^ 4)
      =  2 * 2 * (2 ^ 3)
      =  2 * 2 * 2 * (2 ^ 2)
      =  2 * 2 * 2 * 2 * (2 ^ 1)
      =  2 * 2 * 2 * 2 * 2 * (2 ^ 0)
      =  2 * 2 * 2 * 2 * 2 * 1

function fibonacci(number) {
	if (number == 0 || number == 1) {
		return 1;
	} else {
		return fibonacci(number - 1) + fibonacci(number - 2);
	}
}
console.log(fibonacci(9));
// 55

Definition A CSS pseudo-class: We use it to define a state or a property of the element. It is a way of selecting an “existing HTML element”. A CSS pseudo-element: We use it to style a specified element. It does not select an element, but it creates a virtual element. Let’s take a look at what these definitions mean. A pseudo-class Again, it is related to an existing element, and we use a single colon character in CSS.

:link, :visited, :hover, :active
:focus, :first-child, :nth-child

::before, ::after, ::first-letter

//first-letter selects something that is not an element
//but the first letter of the paragraph
p::first-line {
    color: #fff;
}

Definition Immutability is an important concept, and it means that an element is unchangeable. But the meaning of immutability in JavaScript is a little bit different than other languages. What’s not immutability in JavaScript ‘const’ is not about immutability! We have a new keyword called const in JavaScript version 6, and it seems like making an unchangeable variable like what some other languages do. However, we can change the values of an element in an array using the following notation.

const myArr = [1,2,3];
myArr[0]=6;

//MUTABLE
var myArr = [5,6,7];
myArr.forEach(function(item, index) {
  myArr[index] = item + 1;
});
console.log(myArr);
// [6, 7, 8]

var myArr = [5, 6, 7];
function increase(item) {
    return item +1;
}
var modArr = myArr.map(increase);
console.log(modArr)

Definition The map() function The benefit of using the map() is immutability. Therefore it avoids changing the original array, while ‘for’ and ‘forEach’ transform the original array. Example 1 Let’s take an array and assign it to a new array.

var myArr = [5,6,7]
var newArr = myArr.map(function(item) {
    return item + 1;
});
console.log(newArr);
//Result: [6, 7, 8]

var myArray = [5, 6, 7];
function inc(item) {
    return item + 1;
}
var modArr = myArr.map(inc);
console.log(modArr);
//Result: [6, 7, 8]

var myArr = [5,6,7]
function inc(item){
   return item + 1;
}
function square(item) {
   return item * item;
}
var modArr = myArray.map(inc).map(square);
console.log(modArr);
// Result: [36, 49, 64]

Definition Ems and Rems are units of measurements in CSS and we use them when working with fonts. Em unit is the relative size of its nearest or direct parent. Rem stands for “Root EM”, and this unit allows you to set an em on the HTML(root) font-size. Note Every browser has a default font and that is 16 pixels in most cases, and Rems are always relative to the root font size. Here, I will set the font size at 18 pixels. Example

html {
    font-family: sans-serif;
}
body {
    font-size: 18px;
}

html{
    font-family: sans-serif;
    font-size: 62.5%;
body {
    font-size: 1.6rem;
}

.description{
   font-size: 1rem;
}
.description-text{
   font-size: 2em;
}
.workedfor{
   font-size: 1.5em;
}