angular 2 npm start duplicate identifiers error

Question

I am getting the following errors:

When I run the command (npm-install) in windows cmd it works fine, but when I used the command npm start it gives me an error "duplicate identifiers" in ts files.

I tried to remove node-modules and then I run the command npm install the problem persist.

This is my tsconfig.json:

{
  "compilerOptions": {
    "target": "es5",
    "module": "commonjs",
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "sourceMap": true,
    "baseUrl": "./src/main/webapp",
    "paths": {
    },
    "lib": [
      "es2015",
      "dom"
    ],
    "typeRoots": [
      "node_modules/@types"
    ]
  },
  "exclude": [
    "node_modules",
    "target"
  ],
  "awesomeTypescriptLoaderOptions": {
    "forkChecker": true,
    "useWebpackText": true
  },
  "compileOnSave": false,
  "buildOnSave": false,
  "atom": {
    "rewriteTsconfig": false
  }
}