Strictest JS/TS defaults — oxlint, tsconfig, vitest, oxfmt

.oxfmtrc.json

{
  "$schema": "https://raw.githubusercontent.com/nicksrandall/oxfmt/refs/heads/main/configuration_schema.json",
  "semi": false,
  "singleQuote": true,
  "printWidth": 100,
  "tabWidth": 2,
  "useTabs": false,
  "trailingComma": "all",
  "arrowParens": "always",
  "bracketSpacing": true,
  "endOfLine": "lf",
  "experimentalSortImports": {
    "groups": ["builtin", "external", "internal", ["parent", "sibling", "index"]],
    "newlinesBetween": true
  },
  "ignorePatterns": [
    "**/node_modules/**", "**/dist/**", "**/build/**", "**/.next/**",
    "**/.turbo/**", "**/coverage/**", "**/*.gen.*", "**/*.generated.*",
    "**/routeTree.gen.ts", "**/package.json", "**/tsconfig.json"
  ]
}

.oxlintrc.json

{
  "$schema": "https://raw.githubusercontent.com/oxc-project/oxc/main/npm/oxlint/configuration_schema.json",
  "plugins": ["typescript", "import", "unicorn", "oxc", "eslint"],
  "categories": {
    "correctness": "error",
    "suspicious": "error",
    "perf": "error",
    "style": "off",
    "pedantic": "off",
    "restriction": "off"
  },
  "rules": {
    "typescript/consistent-type-imports": ["error", { "fixStyle": "inline-type-imports" }],
    "typescript/no-import-type-side-effects": "error",
    "typescript/no-unnecessary-type-constraint": "error",
    "typescript/no-useless-empty-export": "error",
    "typescript/no-unused-vars": ["error", { "argsIgnorePattern": "^_", "varsIgnorePattern": "^_" }],
    "typescript/array-type": ["error", { "default": "generic", "readonly": "generic" }],

    "typescript/no-non-null-assertion": "error",
    "typescript/consistent-type-assertions": ["error", { "assertionStyle": "never" }],
    "typescript/no-explicit-any": "error",
    "typescript/no-empty-object-type": "error",
    "typescript/no-unsafe-function-type": "error",
    "typescript/no-dynamic-delete": "error",
    "typescript/no-unnecessary-type-arguments": "error",
    "typescript/no-unnecessary-type-assertion": "error",
    "typescript/no-confusing-non-null-assertion": "error",

    "import/no-duplicates": "error",
    "import/no-self-import": "error",
    "import/no-empty-named-blocks": "error",
    "import/no-commonjs": "error",

    "eslint/no-console": "error",
    "eslint/no-var": "error",
    "eslint/no-useless-constructor": "error",
    "eslint/no-unneeded-ternary": "error",
    "eslint/no-useless-concat": "error",
    "no-underscore-dangle": ["error", { "allow": ["_tag"] }],

    "unicorn/prefer-array-flat-map": "error",
    "unicorn/no-accessor-recursion": "error",

    "no-shadow": "off",
    "require-yield": "off",
    "no-fallthrough": "off",
    "no-await-in-loop": "off",
    "eslint/object-shorthand": "off",
    "no-unused-expressions": "off",
    "no-new": "off",
    "typescript/no-empty-interface": "off",
    "typescript/ban-ts-comment": "off",
    "typescript/no-namespace": "off",
    "typescript/unified-signatures": "off",
    "typescript/no-invalid-void-type": "off",
    "unicorn/consistent-function-scoping": "off",
    "unicorn/no-array-sort": "off",
    "unicorn/no-array-reverse": "off",
    "unicorn/no-new-array": "off",
    "oxc/no-map-spread": "off"
  },
  "overrides": [
    {
      "files": ["**/*.test.ts", "**/*.test.tsx", "**/*.spec.ts", "**/test/**"],
      "rules": {
        "unicorn/no-array-sort": "off",
        "unicorn/consistent-function-scoping": "off",
        "require-yield": "off",
        "eslint/no-console": "off",
        "typescript/no-explicit-any": "off",
        "typescript/no-non-null-assertion": "off",
        "typescript/consistent-type-assertions": "off"
      }
    },
    {
      "files": ["**/*.d.ts"],
      "rules": {
        "typescript/consistent-type-imports": "off",
        "typescript/consistent-type-assertions": "off",
        "typescript/no-explicit-any": "off"
      }
    },
    {
      "files": ["**/*.gen.*", "**/*.generated.*", "**/routeTree.gen.ts", "**/*sst-env.d.ts"],
      "rules": {
        "typescript/no-unused-vars": "off",
        "typescript/no-explicit-any": "off",
        "typescript/no-non-null-assertion": "off",
        "typescript/consistent-type-assertions": "off",
        "unicorn/consistent-function-scoping": "off",
        "import/no-commonjs": "off",
        "eslint/no-console": "off"
      }
    },
    {
      "files": ["vite.config.ts", "vitest.config.ts", "playwright.config.ts"],
      "rules": {
        "eslint/no-console": "off"
      }
    }
  ],
  "ignorePatterns": [
    "**/node_modules/**", "**/dist/**", "**/build/**", "**/.next/**",
    "**/.turbo/**", "**/coverage/**", "**/*.gen.ts", "**/*.generated.ts",
    "**/routeTree.gen.ts"
  ]
}

tsconfig.base.json

{
  "compilerOptions": {
    "strict": true,
    "exactOptionalPropertyTypes": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitOverride": true,
    "noFallthroughCasesInSwitch": true,
    "noUncheckedIndexedAccess": true,
    "noImplicitReturns": true,
    "noUncheckedSideEffectImports": true,

    "module": "NodeNext",
    "moduleResolution": "NodeNext",
    "target": "ES2022",
    "lib": ["ES2022"],
    "skipLibCheck": true,
    "isolatedModules": true,
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "resolveJsonModule": true,
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true
  }
}

vitest.config.ts

import { defineConfig } from "vitest/config"

export default defineConfig({
  test: {
    globals: true,
    include: ["src/**/*.test.ts"],
    sequence: { concurrent: true },
    fakeTimers: { toFake: undefined },
    coverage: {
      provider: "v8",
      reporter: ["text", "html"],
      exclude: [
        "node_modules/",
        "dist/",
        "**/*.d.ts",
        "**/*.config.*",
        "**/vitest.setup.*",
      ],
    },
  },
})