tsconfig.json

{
  "compilerOptions": {
    "lib": ["dom", "es2016", "es2017"],
    "target": "es2016",
    "moduleResolution": "node",
    "jsx": "react", // transpile jsx (also for wallaby)
    "outDir": "./build/",
    "allowSyntheticDefaultImports": true,
    "noImplicitReturns": true,
    "noImplicitAny": true,
    "noImplicitThis": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "strictNullChecks": true,
    "experimentalDecorators": true,
    "preserveConstEnums": true,
    "allowJs": true,
    "noEmitHelpers": true,
    "importHelpers": true,
    "noEmit": true,
    "strict": true,
    "sourceMap": true,
    "types": ["react", "react-native", "jest"],
    "baseUrl": "." //allow absolute imports eg import Button from 'src/comps/Button'
  },
  "exclude": [
    "android",
    "ios",
    "index.android.js",
    "index.ios.js",
    "build",
    "node_modules"
  ],
  "compileOnSave": true
}