nawafi / hw-w02d04-sheetcheat

HW-W02D04 - make a cheatsheet for yourself!

Your review sheet can be in any digital format you want, a word document, a google doc, a markdown file… whatever you want! Submissions will be done via email.

📢 📢 NOTE: This is not all what we cover in the class so feel free to customize your own sheet and add more content

Your cheatsheet should include the following topics:

• Variables:

  • How to declare a variable: (code)

    var home;

  • How to console.log the value of a variable: (code) var home = 'house'; console.log(home);

• conditionals:

  • Operators:

    • How to use the "==" operator:

      It used in to compare values. For example: 5 == 1 the result will be false.

    • How to use the "===" operator:

      It used to compare same value and same type. For example: 'word' === 'word' the result is true. Both of them are Strings and their values are equal.

    • How to use the ">" operator: ` It used to checks if the value of the left operand is greater than the value of the right operand, if yes, then the condition becomes true.For example, (4 > 2) the result will true.

  • How to write an if Statements

    if (condition) {

} else {

}

---

• functions:

  • How you declare a function: function home() {

} * This is the other way to declare a function: function car() { var carName = "Jeep";

} * This is a function that adds 4 to any number:

* This is a function that capitalizes any word: 
  function myFunction() {
var text= 'hellow'
  console.log(text.toUpperCase());

}

console.log('Codecademy'.toUpperCase()); * We use functions because: write a definition

• datatypes:

  • Strings

    • A string is: write a definition a set of letters, single letter and word that is in double or single quotes.
    • You can capitalize a string by:

      var stre = 'hello world.';
      
      console.log(stre.toUpperCase());
      

    • Concatentation is: joining two strings together.
    • An example of concatenation: console.log( " start" + 123 + " hello world!");

  • Numbers:

    • The % operator is: finds the remainder after division two numbers
    • Here is an example of the % operator in use: 7%2=1

  • Arrays:

    • An index is: (index of an array element is the number can be accessed the brackets [])

    • You can access an element in an array like this: (var number = [1, 2, 3, 4]); number[0];
      1

    • Map:

      • .map is an array method that: creates an array filled with all array elements that does not execute the function for array elements without values and does not change the original array.
• An example of map is: var foods = [“rice ”, “spagity”];

var fastFood = foods.map(function(food) { return ‘burger ’ + pizza'; }); * Filter: * .filter is an array method that: creates a new array with elements filter some items out of an existing array.

  * An example of filter is: 

var numbers = [1, 3, 6, 8, 11];

var guess = numbers.filter(function(number) { return number > 7; });

* forEach:
  * .forEach is an array method that: 
    forEach executes a provided function once for each array element.
  *  An example of forEach is: 

var greeting = ['hi', 'hello', 'bye'];

greeting.forEach(function(element) { console.log(element); }); output:hi hello bye

• objects

  • How to access a property
    var person = { firstName:"nawaf", lastName:"Alhathni", eyeColor:"black" }; person.eyeColor();

• loops

  • how to make for loop for (initialization; test condition; iteration statement){ Statement(s) to be executed if test condition is true }

• Querying the DOM

document.querySelector(".example");

• Creating a new element in the DOM

var hello = document.createElement('');

• Appending a new element to the DOM

.appendChild();

• Updating the style properties

document.getElementById().style.property = new style