TypeScript - Access Modifier & get/set

Access Modifier:
private - within the class
public - access from anywhere
protected - within the class and subclasses.

Note: Most of the time if compile time error also, It will generate the file and we can run the file.
How to avoid this ?
1. Delete the js file whatever created earlier. using below command.
Eg. del Customer.js
2. Use below command to not generate the .js file if any compilation error .
Command : tsc -noEmitOnError Customer.ts

Accessors:

Class Customer{
private firstName : string;
private lastName : string;

public getFirstName(): string(){
return this.firstName;
}

public setFirstName(theFirst: string): void {
this.firstName : theFirst;
}
}

Using Get/Set:

* get/set accessors is only supported in ES5 and higher.
* you have to set the compiler flag inorder to compile the code.
Syntax to compile:
tsc --target ES5 -noEmitOnError Customer.ts

Example:
Class Customer{
private _firstName: string;
private _lastName: string;

public get firstName(): string(){
return this._firstName;
}

public set firstName(value: string){
this._firstName = value;
}
}