Somewhat OK TSConfig defaults and explanations

tsconfig.json

/*
  Enabled by "strict":
  - alwaysStrict
  - noImplicitAny
  - noImplicitThis
  - strictNullChecks
  - strictBindCallApply
  - strictFunctionTypes
  - strictPropertyInitialization
  - useUnknownInCatchVariable
  Not needed because we're not emitting:
  - sourceRoot
  - noEmitOnError
  - outFile
  - preserveConstEnums
  - removeComments
  - verbatimModuleSyntax
  - sourceMap
  - inlineSourceMap
  - inlineSources
  - jsxFactory
  - jsxFragmentFactory
  - jsxImportSource
  - downlevelIteration
  - importHelpers
  - noEmitHelpers
  - useDefineForClassFields
  Defaults are fine:
  - allowUnreachableCode: warns by default
  - allowUnusedLabels: warns by default
  - noFallthroughCasesInSwitch: useful
  - noUnusedParameters: _ prefix to ignore feels hacky
  - newLine: let tsc decide
  Misc:
  - incremental: enabled by "composite"
  - noEmit: using "emitDeclarationOnly" instead
  - allowSyntheticDefaultImports: enabled by "esModuleInterop"
  - baseUrl: not recommended
  - declarationDir: set by "outDir" if "declaration" is true
*/
{
  "compilerOptions": {
    // input / output
    "rootDir": "./src" /* all source files in src */,
    "outDir": "./out" /* emit declarations and tsbuildinfo here */,
    "declaration": true /* emit declarations */,
    "declarationMap": true /** generate declaration source maps */,
    "emitDeclarationOnly": true /* emit declarations only */,
    // type checking
    "strict": true /* highly recommended */,
    "exactOptionalPropertyTypes": true /* optional properties can be defined or not defined, but not undefined */,
    "noImplicitOverride": true /* check accidental super class function rename */,
    "noImplicitReturns": true /* check accidental undefined function return */,
    "noPropertyAccessFromIndexSignature": true /* don't allow index to be accessed as property, important for next setting */,
    "noUncheckedIndexedAccess": true /* check index access for undefined */,
    "noUnusedLocals": true /* check unused local variables */,
    "skipLibCheck": true /* don't check lib files */,
    // target runtime
    "target": "esnext" /* modern output */,
    "lib": ["esnext", "dom"] /* change based on target runtime */,
    // module resolution
    "module": "esnext" /* modern modules */,
    "moduleResolution": "bundler" /* bundler will handle resolution */,
    "forceConsistentCasingInFileNames": true /* check file name casing matches import */,
    "allowArbitraryExtensions": true /* allow importing other resources */,
    "allowImportingTsExtensions": true /* otherwise you have to add .js to your imports */,
    "moduleDetection": "force" /* ensure all non-declaration files are modules */,
    "isolatedModules": true /* warn about things that per-file bundlers can't handle */,
    "resolveJsonModule": true /* allow json imports */,
    "esModuleInterop": true /* allow default imports from commonjs modules */,
    "composite": true /* allow project references */,
    "allowJs": true /* allow importing js from ts */,
    "checkJs": true /* type check js imports */,
    "jsx": "react-jsx" /** allow jsx */
  }
}