You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
84 lines
1.5 KiB
84 lines
1.5 KiB
# Javascript Fundamentals Review
|
|
|
|
## Primative Data Types
|
|
|
|
Javascript has several basic data types:
|
|
|
|
```javascript
|
|
'this is a string' // string (text)
|
|
123 // number (int)
|
|
1.2 // number (float)
|
|
true // boolean
|
|
false // boolean
|
|
```
|
|
|
|
## Variables
|
|
|
|
Declaring variables is done with the keyword `var`. Variables are dynamically typed (decided during execution) since there is no compilation process.
|
|
|
|
```javascript
|
|
var foo = 'string';
|
|
var bar = 1;
|
|
```
|
|
|
|
Reassignment is done by omitting the var keyword. Variables are loosely typed (can be reassigned to any other value, regardless of their initial value)
|
|
|
|
```javascript
|
|
var foo = 'a string';
|
|
foo = 123.4;
|
|
```
|
|
|
|
## Functions and Scope
|
|
|
|
Declare functions with keyword `function`. Do not need to specify return type.
|
|
|
|
```javascript
|
|
function myFunc(){
|
|
return 5;
|
|
}
|
|
```
|
|
|
|
To execute a function, invoke its name with parentheses
|
|
|
|
```javascript
|
|
myFunc();
|
|
```
|
|
|
|
Can pass parameters into functions
|
|
|
|
```javascript
|
|
function addFive(numberToAddFiveTo){
|
|
return numberToAddFiveTo + 5;
|
|
}
|
|
addFive(6); // returns 11
|
|
```
|
|
|
|
Variables declared inside a function cannot be accessed outside of it
|
|
|
|
```javascript
|
|
function foo(){
|
|
var myVar = 1;
|
|
return myVar;
|
|
}
|
|
console.log(myVar); // error
|
|
```
|
|
|
|
but variables declared outside a function are accessible within it
|
|
|
|
```javascript
|
|
var myVar = 1;
|
|
function foo(){
|
|
return myVar;
|
|
}
|
|
console.log(foo());
|
|
```
|
|
|
|
## Objects/Arrays
|
|
## Equality
|
|
## Control Flow (loops, if/else)
|
|
## Functions are objects
|
|
## Events
|
|
## Callbacks
|
|
## Asynchronicity
|
|
## Constructor Functions
|