Angular2 Duplicate identifier 'PropertyKey'

Question

I am building an angular2 application using angular-cli. angular-in-memory-web-api was not installed by default.

So I searched

Answer 1

It seems like you are compiling in the node_modules folder, so, in your tsconfig.json (that I presume you have) make sure to set your exclusions for the compiler to ignore:

{
  "compileOnSave": true,
  "compilerOptions": {
    <...>
  },
  "exclude": [
    "node_modules"
  ] 
}