Primitive Types in TypeScript
Simple types are also called the primitive types and they belong to built-in predefined types found in TypeScript. The primitive data type are number, string, boolean, null type and undefined types. There are the following primitive or built-in types in TypeScript, which are described below.
Number Type
The number primitive type is the same as the JavaScript primitive type and represents double-precision 64-bit IEEE (Institute of Electrical and Electronic Engineers) 754 format floating point values. The number keyword is used to represent number type values.
Syntax
var variablename:number;
var q=anyNumericValue;
Example of Number Type
NumberType.ts
class NumberTypeOfTypeScript {
MyFunction()
{
var p: number;
p = 1;
var q = 2;
var r = 3.33;
alert("Value of P=" + p + " Value of q=" + q + " Value of r=" + r);
}
}
window.onload = () =>{
var value = new NumberTypeOfTypeScript();
value.MyFunction();
}
default.html
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title>TypeScript HTML App</title>
<link rel="stylesheet" href="app.css" type="text/css" />
<script src="app.js"></script>
</head>
<body>
<h1>Number Type in TypeScript</h1>
<div id="content"/>
</body>
</html>
app.js
var NumberTypeOfTypeScript = (function () {
function NumberTypeOfTypeScript() { }
NumberTypeOfTypeScript.prototype.MyFunction = function () {
var p;
p = 1;
var q = 2;
var r = 3.33;
alert("Value of P=" + p + " Value of q=" + q + " Value of r=" + r);
};
return NumberTypeOfTypeScript;
})();
window.onload = function () {
var value = new NumberTypeOfTypeScript();
value.MyFunction();
};
Output
![number-type-in-typescript.jpg]()
String Type
The string primitive type is the same as the JavaScript primitive type and it represents a sequence of characters stored as Unicode UTF-16 code.
Syntax
var variable:string;
var q="someString";
Example of String Type
StringType.ts
class StringTypeOfTypeScript {
Myfunction() {
var s: string;
s="TypeScript"
var empty = "";
var abc = "abc";
alert("Value of s="+ s+" Empty string="+ empty+" Value of abc ="+abc) ;
}
}
window.onload = () =>{
var value = new StringTypeOfTypeScript();
value.Myfunction();
}
default.html
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title>TypeScript HTML App</title>
<link rel="stylesheet" href="app.css" type="text/css" />
<script src="app.js"></script>
</head>
<body>
<h1>String Type in TypeScript</h1>
<div id="content"/>
</body>
</html>
app.js
var StringTypeOfTypeScript = (function () {
function StringTypeOfTypeScript() { }
StringTypeOfTypeScript.prototype.Myfunction = function () {
var s;
s = "TypeScript";
var empty = "";
var abc = "abc";
alert("Value of s=" + s + " Empty string=" + empty + " Value of abc =" + abc);
};
return StringTypeOfTypeScript;
})();
window.onload = function () {
var value = new StringTypeOfTypeScript();
value.Myfunction();
};
Output:
![string-type-in-typescript.jpg]()
Boolean Type
The boolean primitive type is the same as the JavaScript primitive type and represents a logical value; either true or false.
Syntax
var p:bool;
var q=true;
Example of Boolean Type
BooleanType.ts
class booleanTypeofTypeScript {
MyFunction() {
var lie: bool;
lie = false;
var a = 12;
if (typeof (lie) == "boolean" && typeof (a) == "boolean") {
alert("Both is boolean type");
}
if (typeof (lie) == "boolean" && typeof (a) != "boolean") {
alert("lie is boolean type and a is not!")
}
else {
alert("a is boolean type and lie is not!");
}
}
}
window.onload =()=> {
var access = new booleanTypeofTypeScript();
access.MyFunction();
}
default.html
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title>TypeScript HTML App</title>
<link rel="stylesheet" href="app.css" type="text/css" />
<script src="app.js"></script>
</head>
<body>
<h1>Boolean Type in TypeScript</h1>
<div id="content"/>
</body>
</html>
app.js
var booleanTypeofTypeScript = (function () {
function booleanTypeofTypeScript() { }
booleanTypeofTypeScript.prototype.MyFunction = function () {
var lie;
lie = false;
var a = 12;
if(typeof (lie) == "boolean" && typeof (a) == "boolean") {
alert("Both is boolean type");
}
if(typeof (lie) == "boolean" && typeof (a) != "boolean") {
alert("lie is boolean type and a is not!");
} else {
alert("a is boolean type and lie is not!");
}
};
return booleanTypeofTypeScript;
})();
window.onload = function () {
var access = new booleanTypeofTypeScript();
access.MyFunction();
};
Output:
![boolean-type-in-typescript.jpg]()
Null Type
The Null primitive type is the same as the JavaScript primitive type and represents a null literal and it is not possible to directly reference the null type value itself.
Syntax
var vaiablename:number=null;
var q=null;
Example of Null Type
NullType.ts
class NullTypeinTypeScript {
MyFunction() {
var p: number = null;
var x = null;
if (p== null) {
alert("p has null value!");
}
else { alert("p has a value"); }
}
}
window.onload = () =>{
var value = new NullTypeinTypeScript();
value.MyFunction();
}
default.html
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title>TypeScript HTML App</title>
<link rel="stylesheet" href="app.css" type="text/css" />
<script src="app.js"></script>
</head>
<body>
<h1>Null Type in TypeScript</h1>
<div id="content"/>
</body>
</html>
app.js
var NullTypeinTypeScript = (function () {
function NullTypeinTypeScript() { }
NullTypeinTypeScript.prototype.MyFunction = function () {
var p = null;
var x = null;
if(p == null) {
alert("p has null value!");
} else {
alert("p has a value");
}
};
return NullTypeinTypeScript;
})();
window.onload = function () {
var value = new NullTypeinTypeScript();
value.MyFunction();
};
Output:
![null-type-in-typescript.jpg]()
Undefined Type
The Undefined type is the same as the JavaScript primitive type and is the type of the undefined literal. The undefined type is a sub-type of all types.
Syntax
var p:number=undefined;
var q=undefined;
Example of Undefined Type
UndefinedType.ts
class UndefinedTypeOfTypeScript {
Myfunction() {
var p: number;
var x = undefined;
if (p == undefined && x == undefined) {
alert("p and x is undefined");
}
else { alert("p and c cannot undefined"); }
}
}
window.onload = () =>{
var value = new UndefinedTypeOfTypeScript();
value.Myfunction();
}
default.html
<!DOCTYPE html>
<html lang="en" xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta charset="utf-8" />
<title>TypeScript HTML App</title>
<link rel="stylesheet" href="app.css" type="text/css" />
<script src="app.js"></script>
</head>
<body>
<h1>Default Type in TypeScript</h1>
<div id="content"/>
</body>
</html>
app.js
var UndefinedTypeOfTypeScript = (function () {
function UndefinedTypeOfTypeScript() { }
UndefinedTypeOfTypeScript.prototype.Myfunction = function () {
var p;
var x = undefined;
if(p == undefined && x == undefined) {
alert("p and x is undefined");
} else {
alert("p and c cannot undefined");
}
};
return UndefinedTypeOfTypeScript;
})();
window.onload = function () {
var value = new UndefinedTypeOfTypeScript();
value.Myfunction();
};
Output:
![undefind-type-in-typescript.jpg]()