Blocks, if-statements, switch (Lesson 2 with Hassan)

GOOD TO REMEMBER!

{} curly brackets
[] square brackets
() parentesis / brackets
: colon
; semicolon
" quotes / double quotes
' quotes / single quotes
` back ticks

BLOCK

We use it to group expressions with each other
Curly brackets ({}) are used for the block.
It is used with:

• if
• while
• for
• functions

IF-STATEMENTS

-if to specify a block of code to be executed, if a specified condition is true;
-else if to specify a new condition to test, if the first condition is false
-else to specify a block of code to be executed, if the same condition is false;

Example 1:

if (condition1) {

  //  block of code to be executed if condition1 is true

} else if (condition2) {

  //  block of code to be executed if the condition1 is false and condition2 is true

} else {

//  block of code to be executed if the condition1 is false and condition2 is false

}

Example 2:

const condition = true

if(condition) {

    console.log("sant")

} else {

    console.log("falskt")

} 

or

Conditional (Ternary) Operator

const condition = true

condition  ? console.log("sant") : console.log("falskt")

Switch statement

To select one of many code blocks to be executed.

How it works:

• The switch expression is evaluated once.
• The value of the expression is compared with the values of each case.
• If there is a match, the associated block of code is executed.
• If there is no match, the default code block is executed.

Example 3:

switch(expression) {

    case x:

      // code block

      break;

    case y:

      // code block

      break;

    default:

      // code block

}

Math.ceil() vs Math.round()

The Math.ceil() function always rounds a number up to the next largest integer.

• Math.ceil(null) returns integer 0 and does not give a NaN error

The round() method rounds a number to the nearest integer.