TypeScript/ES6: what is an “:” in the below context?

I understand below two usages in TS/ES6.

1. Below, a variable myname of type string which is going to be constant(final) is declared.

   const myname: string = ‘abcd’;

2. Below a variable/function initialPath is declared and is assigned a function body using the => operator.

   const initialPath = ({pathRoot, myvar = ”, locale = ”}) =>
   path.join(process.cwd(), pathRoot, myvar, locale.toLowerCase());

But I am not sure of the below usage, what is : in the below doing.

module.exports = {
  application: myname,
  myservicePostfix,
  loadablePath: ({pathRoot, myvar}) =>
    path.join(basePath({pathRoot, myvar}), 'loadable.json')
}

-> does application: myname mean that application = myname and application is of type typeof(myname).
-> similarily what does loadablePath: above mean