Modules,NameSpaces,Exports, Imports in TypeScript

 Module is a collection of variables, functions, classes and interfaces.

 This will be reusable across different other modules with in a project.

Scenario

    <>.ts                                    <>.ts
      |                                            |
 export class c1                       import{c1,c2} from "./module1";
  {..}                                          obj=new c1();
 export class c2                              ..
  {..} 

     |                                                |
  [module1]                                [module2]



                                                       <>.ts
                                                          |
                                               import{c1,c2} from "./module1";
 
                                                          ....
                                                    [module3]

Syntax:

   export namespace <namespacename>
   {
     
        export let <varname>:<type>=value;

        export function <funcname>()
         { .. }

        export class <classname>
         { .. }

       export interface <interfacename>
         { .. }

    }


  ->export members are module public, this will be accessible outside
    module
  ->export members of one module can be accessed | referenced in another
    using "import" keyword.

NameSpace:

namespace is a logical container to group related members.

      eg:
          namespace ns1               obj1=new ns1.c1();                
               |
            class c1                        obj2=new ns2.c1();
             {}
          namespace ns2
               |
           class c1
              {}
    ->namespace is an optional


Now, I have a requirement

   module1.ts                                              module2.ts
       |                                                             |
  namespace inventory   --------------------->importing export members of
  export class category
  export class product                                       module1







Module2.ts

import{inventory} from "./Module1";
let cateobj=new inventory.category("c001","mobiles");
let prodobj=new inventory.product("p001","samsung");
cateobj.display();
prodobj.display();


Output

PS C:\Examples> tsc.cmd Module2.ts
PS C:\Examples> node Module2
c001 mobiles
p001 samsung

Note: Here  Module2.ts compilation will perform all the dependent modules[Module1.ts]
compilation automatically
 
    tsc Module2.ts------>   compilation of Module2.ts and Module1.ts
                                    |
                                Module2.js
                                Module1.js


Note: Namespace naming is optional

Without Namespace



















Output
PS C:\Examples> node Module2      
c001 mobiles
p001 samsung


Working with multiple Modules Examples









Modify the Module2.ts code as below

import{category,product} from "./Module1";
let cateobj=new category("c001","mobiles");
let prodobj=new product("p001","samsung");
cateobj.display();
prodobj.display();
export class emp{}
export class dept{};
export{category,product};


Module3.ts