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 had the same error and fixed it by typing:

npm install --save typescript@latest

package.json now has the latest ts version and ts compiler is 2.2.2.