Javascript Basic

1. Data Types

1. String "Any text"
2. Number 12345
3. Boolean true or false
4. Null null
5. Undefined undefined
6. Symbol symbol('something')
7. Object {key: 'value'}
   • array [1,"text", false]
   • function function name(){}

number 1-6 are six primitive types

2. Basic Vocabulary

var a = 7 + "2";

var = keyword/reserved word
any word that is part of the vocabulary of the programming languange is called a keyword(a.k.a reserve word).
Example: var = + if for...

a = variable
a named reference to a value is a variable

= and + = operator
operators are reserved-words that perform action on values and variables
Example: + - = * in === typeof != ...

var a = 7 + "2"; = statement
a group of words, numbers and operators that do a task is a statement

7 + "2" = expression
a reference, value or a group of reference(s) and value(s) combined with operator(s). which result in a single value.

3. Object
An object is a data type in Javascript that is used to store a combination of data in a simple key-value pair.

var user = {
   name: "Lourdes Suello",
   yearOfBirth: "1991"
   calculateAge: function(){
    // some code to calculate age
  }
}

name, yearOfBirth, calculateAge = Key
these are the keys in user object.

"Lourdes Suello", "1991", function(){} = Value
these are the values of the respective keys in user object.

function(){} = Method
if a key has a function as a value its called a method

4. Function
A function is a simple bunch of code bundled in a section. This bunch of code ONLY runs when the function is called. Functions allow for organizing code into section and code reusability.