TypeScript If Else Control Statement

This statement is basically used to check certain conditions or sometimes we reqiure to execute certain statement when specified condition true.

Syntax:

if (condition)
   //code that will run if the condition is true

TypeScript If Example 1

								
var msg:string;
if (age > 20)
this.msg = "Invalid person for test";							

TypeScript If..Else Statement

When specified condition failed, else statement will be executed.

Syntax:

if (condition)
   //code that will run if the condition is true
else
  //code that will run if the condition is false

TypeScript If Else Example 2

CheckAge(age:number) : string
{ 
	if (age < 20)   
		this.msg = 'Invalid person for test';
	else
		this.msg = 'Valid person for test';
  
	return this.msg;
}
								

TypeScript If..Else If Statement

When there are situations when we need to test several conditions thenuse else if condition.

Syntax:

if (condition1)
   //code that will run if the condition1 is true
else if(condition2)
  //code that will run if the condition2 is true
else if(condition3)
  //code that will run if the condition3 is true
else
  //code that will run if the all contitions fails

TypeScript If Else.. If Example 3

CheckNumber(num:number) : string
{ 
   if (num > 0)
	  msg = "Positive number";
   else if(num < 0)
	  msg = "Negetive number";
   else
	  msg = "Not a number";
  
	return msg;
}