Welcome Typescript interview questions and answers for beginners,Here are the
some tricky typescript interview question and answers collection
which is ask in interview. May it will help you to crack you typescript
interview.
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| Typescript interview questions and answers |
1.What is namespace in Typescript? Write
the declaration of namespace.
I think
Everyone familiar with namespace of other languages , here also in
TypeScript a namespace is just a collection of classes by which we can
logically categories. If we want to access any class from out side of the
namespace then we need to export keyword.
namespace People
{
export class Boss
{
}
export class Employee
{
}
export interface Iofficework
}
2.What is Typescript?
TypesScript is
known as Object oriented programming language developed and maintained by
Microsoft. Which is provide you to optional parameters,classes and
interfaces.TypeScript is nothing but JavaScript and some additional features
i.e. ES6 features.Whenever we compile the TypeScript code it first convert in
JavaScript then it run and we get output
3Difference between typescript and javascript?
1.Typescript is
a superset of JavaScript whereas JavaScript is a scripting language.
2.Typescript
have interface concept but JavaScript havan't.
3.TypeScript
dosen't run in browser where JavaScript runs.
4.TypeScript
have classes whereas JavaScript have functions.
5.Typescript
support module whereas JavaScript dosen't support modules.
6.In typescript
Number,string are the interfaces whereas In, JavaScript Number,string are the
Object.
4.What are the key features of typescript?
TypeScript
supports different browsers or node.js versions, and optimizes the resulting
JavaScript. It is much easier to write clean, consistent code across a project
and development team..
5.When to use super keyword in typescript.
In
typescript,Super keyword is used to reference base class properties and the
base class constructor.
6.How to access static methods in
TypeScript
7.What Are Classes In Typescript?
The concept of
classes is very similar to .NET/Java. A Class can have constructor, member
variables, properties and methods. TypeScript also allows access modifiers
“private” and “public” for member variables and functions.
8.Tell me the command for installing
typescript.
npm install -g typescript
9.What Are The Benefits Of Typescript?
TypeScript has
following benefits:
1.Intellisense
2Impose coding
guidelines
3.Offers type
checking
4.It helps in
code structuring
5.Compile time
error checking
6.Use class
based object oriented programming
10.What is the typescript extension and how
you compile.
Typescript
extension is '.ts'. It is just a javascript file ,when we compile typescript
file, just after compilation it convert into '.js' file.
Step to complie
typescript program
1. tsc 'your
typeScript File Name'
For example, to
compile “program.ts”:
tsc program.ts
After
complilation you will get
program.js
11.How to declare variable in Typescript ?
var name:string="sham"
var phone:string="123456"
12.How do you declare undefined variable?
var name:string;
var phone:int;
13.How to
declare and initialize array in Typescript ?
var names:string[];
-- Declaration
names=["a","b","c","d"]
-- Initialization
14.How to
achieve inheritance in Typescript ?
15.How to make
a module in Typescript ?
16.What is role
of constructor in Typescript ?
Constructor is responsible for initializing the
variables of the class.
17.How to
initialize the static variables ?
class office
{
static phoneNo:number=101;
}
office.phoneNo=106;
console.log(office.phoneNo) ;
18.What is the
difference between var and let in Typescript?
1.var
declaration done at function scoped and let declaration done at block scoped.
2.var allow you
to re-declare the same variable in the same scope. whereas let will not
19.How to
define a global variable in a typescript module.
20.How to export a variable.
export var demo =
[1,2,3];
21.What
is the role of var keyword in typescript.
var
is key it helps us to creating an object of a class.
