Error in angular-token.model.d.ts

[nzacca]

I'm submitting a...

• Regression (a behavior that used to work and stopped working in a new release)
• Bug report
• Performance issue
• Feature request
• Documentation issue or request
• Other... Please describe:

Current behavior

When building with strictNullChecks=true, the following error is raised:

ERROR in node_modules/angular-token/lib/angular-token.model.d.ts(11,5): error TS2411: Property 'name' of type 'string | undefined' is not assignable to string index type 'string'.
node_modules/angular-token/lib/angular-token.model.d.ts(12,5): error TS2411: Property 'userType' of type 'string | undefined' is not assignable to string index type 'string'.

Expected behavior

No error.

What is the motivation / use case for changing the behavior?

I would like to be able to use this library with strictNullChecks set to true.

Environment

Angular-Token version: 7.0.1
Angular version: 7
Typescript version: 3.2.4 & 3.4.5

Bundler

• Angular CLI (Webpack)
• Webpack
• SystemJS

Browser:

• Chrome (desktop) version XX
• Chrome (Android) version XX
• Chrome (iOS) version XX
• Firefox version XX
• Safari (desktop) version XX
• Safari (iOS) version XX
• IE version XX
• Edge version XX

Others:
N/A

Notes:
The issue is with the RegisterData definition here:

https://github.com/neroniaky/angular-token/blob/master/projects/angular-token/src/lib/angular-token.model.ts#L19

The following proposed change to the index signature should work since the RegisterData definition with the named properties allows an undefined string value for userType and name:

export interface RegisterData {
  [key: string]: string | undefined;
}

See the following for a demo of the issue and solution.

Edit: Updated environment version to indicate Typescript version.