Variables in TypeScript

• • Variable is a named space in memory that stores a value.
  • Variables can include characters or digits or both. But they cannot begin with digits.
  • They cannot contain special symbols except underscore(_) or dollar sign($).
  • We cannot use keywords as variables and they must be unique within a scope.
  • They are case-sensitive and cannot contain spaces.
  • Some examples of Identifiers are: firstName, last_Name, number1 etc.
  • You should declare a variable using a data type before you use it.
  • Use var keyword to declare a variable.
  • For example: var value:string=”Hello”;

var value:string=”Hello”;	Declaring a variable of a particular data type and storing a value in it.
var value:string;	Declaring a variable of a particular data type. As we are not assigning a value to it, by default undefined is assigned to it
var value=”Hello”;	Declaring a variable and storing a value in it. Data type of the variable is determined by the type of value stored in it. Hence it will be of string type
var value;	Declaring a variable. As nothing is specified, the data type will be any and value will be undefined