angular 2 typescript An implementation cannot be declared in ambient contexts

Question

I am new to typescript and I am trying to create a function for an angular 2 directive. Can anyone explain, in language for n00bs, what the error is trying to tell me when I

Answer 1

I ran across this rather unusual compile-time Typescript error error TS1183: An implementation cannot be declared in ambient contexts.

It started after I had copy/pasted some sourcecode that had export declare class. I noticed when I changed it to export class this error went away.

Change This:

export declare class Foo {
}

To This:

export class Foo {
}