[BUG][TYPESCRIPT] typescript-angularjs enum

Description

Given an API with an enum:

foo:
  stype: string
  enum: [FOO, BAR]

the typescript-angularjs (and other typescript templates) generates enums such as:

export namespace Example {
  export enum FooEnum {
    FOO = <any> 'FOO',
    BAR = <any> 'BAR'
  }
}

I'm not sure about that <any> casting as it produces a different API than without it.

When compiling to .js/.d.ts the output is vastly different because of the <any> cast:

export namespace Example {
  export enum FooEnum {
    FOO,
    BAR
  }
}

This could be argued to be a bug in tsc but on the other hand I dont see the purpose of the casting and what the intended outcome is. By looking at just the type information both FOO and BAR can be anything so tsc is not entirely wrong either.

It also seems to differ with other typescript templates:

• typescript-axios, typescript-fetch, etc uses no casting -> works as expected
• typescript-node uses same cast -> same problem
• typescript-angular generates some other weirdness I cannot identify if it is correct but it looks like it would work.

openapi-generator version

Tested 4.2.2 and 4.3.0, same issue.

OpenAPI declaration file content or url

openapi.yaml:

openapi: 3.0.0
info:
  title: foo
  version: 0.0.0
paths:
  /foo:
    post:
      requestBody:
        content:
          application/json;charset=utf-8:
            schema: {$ref: '#/components/schemas/Body'}
        required: true
      responses:
        '204':
          description: No Content
components:
  schemas:
    Body:
      type: object
      properties:
        foo:
          type: string
          enum: [FOO, BAR]

tsconfig.json:

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "declaration": true,
    "outDir": "./dist",
    "lib": ["es2017", "dom"],
    "rootDir": "./src",
    "strict": true,
    "moduleResolution": "node",
    "esModuleInterop": true
  }
}

Command line used for generation

openapi-generator generate -g typescript-angularjs -i openapi.yaml -o src/typescript-angularjs
tsc

Steps to reproduce

1. Create above files
2. Run commands from above
3. Check created files in dist/typescript-angularjs/model/Body.d.ts

Suggest a fix

I personally think the cast should be removed and I dont see what it intends to solve. I can gladly create a PR to fix this if someone can acknowledge the issue.

Start with the typescript-angularjs modelEnum.mustache template and compare it with the typescript-axios and typescript-fetch templates; also inspect the typescript-node model.mustache cast. Run the supplied openapi.yaml generation commands and tsc, then verify the generated Body.d.ts enum output matches the intended TypeScript API without the problematic cast.