Typescript-node - TS2300: Duplicate identifier 'default`

Description

I installed swagger-codegen@2 on a mac to make sure that typescript-node was included as a language. When generating a typescript-node client I get the following errors:

    protected authentications = {
        'default': <Authentication>new VoidAuth(),
        'default': new OAuth(),
    }

error TS2300: Duplicate identifier ''default''

Which I think in turn causes

    public setDefaultAuthentication(auth: Authentication) {
	this.authentications.default = auth;
    }

error TS2322: Type 'Authentication' is not assignable to type 'OAuth'.
Property 'accessToken' is missing in type 'Authentication'.

Swagger-codegen version

V2.4.1

Swagger declaration file content or url

I cannot provide the complete JSON as it is private but I could provide a snippet if I can get a pointer as to where there might be an issue.

Command line used for generation

swagger-codegen generate -i swagger.json -l typescript-node

Steps to reproduce

As above

Related issues/PRs

Suggest a fix/enhancement

Reproduce the issue with the swagger-codegen generate -i swagger.json -l typescript-node command and inspect the generated authentications block. Use a Swagger declaration that produces both default entries, then verify the generated client has no duplicate identifier and that setDefaultAuthentication type-checks.