tsconfig.json

{
  "compilerOptions": {
    "allowJs": true /* Allow JavaScript files to be type checked. */,
    "alwaysStrict": true /* Parse in strict mode. */,
    "esModuleInterop": true /* matches compilation setting */,
    "isolatedModules": true /* to match webpack loader */,
    "jsx": "preserve" /* Preserves jsx outside of Next.js. */,
    "lib": [
      "dom",
      "es2017"
    ] /* List of library files to be included in the type checking. */,
    "module": "esnext" /* Specifies the type of module to type check. */,
    "moduleResolution": "node" /* Determine how modules get resolved. */,
    "noEmit": true /* Do not emit outputs. Makes sure tsc only does type checking. */,

    /* Strict Type-Checking Options, optional, but recommended. */
    "noFallthroughCasesInSwitch": true /* Report errors for fallthrough cases in switch statement. */,
    "noUnusedLocals": true /* Report errors on unused locals. */,
    "noUnusedParameters": true /* Report errors on unused parameters. */,
    "strict": true /* Enable all strict type-checking options. */,
    "target": "esnext" /* The type checking input. */
  }
}