# Control Flow in JavaScript: If, Else, and Switch

`Everything is not availale for everyone.`

Control Flow: The order in which code runs based on the conditions.  
Instead of code run all line by line it has to ignore some lines through some coditions.

### Use `if` conditions

```javascript
let marks = 40

if(marks > 33){ // if with condtion of 33 value
    console.log('you are passed') // condtion true then run
}
// console.log (print) will only run if condtion match the values
```

### Handle the other conditions

```javascript
let marks = 40

if(marks > 33){ 
    console.log('you are passed')
} else {
    console.log('you are failed') //here is the others condition 
}
// In this code. console.log(print) statement will run. 
```

> now we execute the condition with `if` and `else` one condition will run always

### Lets add more conditions to discuss like

```javascript
let marks = 40

if(marks > 33){ 
    console.log('you are passed')
if (marks > 90){ // add more condition with another values
    console.log('Got Grade A') 
if (marks > 75){ // add more condition with another values
    console.log('Got Grade B') 
} else {
    console.log('you are failed') 
}
```

> runs code by checking conditions one by one and print the statement as per condition

## Switch Statement

Used when you compare **one value with many options**

```javascript
let day = 2;

switch (day) {            // difines variables 
  case 1:                 // case used for match the values 
    console.log("Monday");// if true then print 
    break;                // done and skip next (flow break)
  case 2:                     // previous not match 
    console.log("Tuesday");   // what need to be done
    break;                    // if match the end it
  case 3:
    console.log("Wednesday");
    break;
  case 4:
    console.log("Thursday");
    break;
  case 5:
    console.log("Friday");
    break;
  case 6:
    console.log("Saturday");
    break;
  case 7:
    console.log("Sunday");
    break; 
  default:                 // if none of condition matched 
    console.log("Invalid day");// run this code 
}
```

> We can use Switch if we have multiple conditions with fixed values

### When to use of `if -else` or `switch`

| Use Case | Best Choice |
| --- | --- |
| Checking ranges (age > 18) | if-else |
| Multiple specific values | switch |
| Complex logic | if-else |
| Clean fixed options | switch |

### Summary

if we have conditions to run the code then **Control flows** comes in the pictures

*   Use `if` → single condition
    
*   Use `if-else` → two paths
    
*   Use `else if` → multiple conditions
    
*   Use `switch` → many fixed values