TypeScript - [Subsequent property declarations must have the same type] - Multiple references to the same type definitions

Because of the feedback above I believe I have found a solution to my problem.

1. Run 'npm uninstall react -g' to uninstall the react package from your global cache.

2. Create a manual reference in your package.json file to the @types/react package.

   "devDependencies": { "@types/react": "16.4.13"}

My final package.json file looked like this:

{  "name": "fungalai",  "version": "1.0.0",  "dependencies": {    "react": "16.4.2",    "react-dom": "16.4.2"  },  "devDependencies": {    "@types/flux": "3.1.7",    "@types/react": "16.4.13",    "axios": "^0.18.0",    "deep-diff": "^1.0.1",    "babel-core": "^6.26.3",    "babel-loader": "^7.1.4",    "babel-polyfill": "^6.26.0",    "babel-preset-es2015": "6.24.1",    "babel-preset-react": "6.24.1",    "babel-preset-stage-0": "^6.24.1",    "create-react-class": "^15.6.3",    "expose-loader": "^0.7.5",    "jszip": "^3.1.5",    "flux": "3.1.3",    "ts-loader": "^4.3.0",    "typescript": "3.0.1",    "uglifyjs-webpack-plugin": "^1.2.5",    "webpack": "^4.8.3",    "webpack-cli": "^2.1.4"  }}

and tsconfig.json like this:

{  "compilerOptions": {    "module": "commonjs",    "moduleResolution": "node",    "target": "es5",    "sourceMap": true,    "jsx": "react",    "lib": [ "es6", "dom" ],     "removeComments": true,    "typeRoots": [      "/node_modules/@types",      "/Types/"    ]  },  "compileOnSave": false,  "exclude": [    "/node_modules/",    "/bin",    "/obj"  ]}

This seems to have resolved the errors.

I found the following github issue, which I am pretty certain identifies the root cause of the problems you were facing: https://github.com/DefinitelyTyped/DefinitelyTyped/issues/25145

So you'll get @types/react at version 16.3.9 and @types/react-dom at version 16.0.5, because you explicitly asked for those. However, @types/react-dom lists a dependency on @types/react as the following: "@types/react": "*"

[this] interprets as "the latest version of @types/react", so it installs an additional version of the package.

So you will have versions v16.3.9 and v16.3.12 of the types package simultaneously being used, which causes the error.

There's two ways I know of to fix this:

1. Update to the latest version of the @types/react package in your package.json
2. Add a resolutions section to your package.json to tell Yarn to resolve the dependency differently.

This error occurs when you have a dependency and a sub-module with the same dependency in a different version. The right way to fix this is including a "resolutions" section in your package.json. The following example explain how to you "resolutions":package.json

{  "name": "project",  "version": "1.0.0",  "dependencies": {    "left-pad": "1.0.0",    "c": "file:../c-1",    "d2": "file:../d2-1"  },  "resolutions": {    "d2/left-pad": "1.1.1",    "c/**/left-pad": "^1.1.2"  }}

Documentation reference: https://classic.yarnpkg.com/en/docs/selective-version-resolutions/