tsconfig.json

{
  "extends": "./paths.json",
  "compilerOptions": {
    "target": "ES6",
    "lib": [
      "dom",
      "dom.iterable",
      "esnext"
    ],
    "downlevelIteration": true,
    "allowJs": true,
    "skipLibCheck": true,
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "noFallthroughCasesInSwitch": true,
    "module": "esnext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "noImplicitAny": false,
    "strictNullChecks": false,
    "noEmit": true,
    "jsx": "react-jsx"
  },
  "include": [
    "src"
  ]
}

actually see a recent change to this file, not sure if it matters though

I just tried reverting to the previous value es5, reactjs still doesn't fail on the compiling error that it should.