tsconfig.json

// TypeScript configuration that is common to all environments we work in.
{
  // https://www.typescriptlang.org/tsconfig
  "compilerOptions": {
    // Type Checking
    // =============
    // Note that we enumerate each setting related to type checking so that we
    // can document our rationale.

    // Help catch refactoring errors.
    "allowUnreachableCode": false,

    // Help catch refactoring errors.
    "allowUnusedLabels": false,

    // Enforce ES' strict mode at runtime
    "alwaysStrict": true,

    // Would be nice, but in practice it is too strict.
    "exactOptionalPropertyTypes": false,

    // Covered by Biome as an error.
    "noFallthroughCasesInSwitch": false,

    // Make sure that we annotate any code TypeScript cannot infer types of.
    "noImplicitAny": true,

    // Help catch refactoring errors.
    "noImplicitOverride": true,

    // Usually a programmer error.
    "noImplicitReturns": true,

    // Make sure that we annotate any code TypeScript cannot infer types of.
    "noImplicitThis": true,

    // Use different syntax between explicitly defined properties and indexed
    // values, so it is clear to the reader.
    "noPropertyAccessFromIndexSignature": true,

    // Rather than assume that indexed values always exist; let's be explicit.
    "noUncheckedIndexedAccess": true,

    // Help catch refactoring errors.
    "noUnusedLocals": true,

    // Help catch refactoring errors.
    "noUnusedParameters": true,

    // Make sure that we opt into future strict mode features.
    "strict": true,

    // Make sure that call() and apply() are type checked.
    "strictBindCallApply": true,

    // Catch subtle bugs around functions as arguments.
    "strictFunctionTypes": true,

    // Prevent most null-pointer exceptions.
    "strictNullChecks": true,

    // Don't assume that properties are always initialized.
    "strictPropertyInitialization": true,

    // JavaScript allows arbitary types to be thrown.
    "useUnknownInCatchVariables": true
  }
}