Presets

Presets are named bundles of default options that give a project a sensible starting point without requiring every option to be listed explicitly. A preset sets defaults for typescript, runtime, tools, extensions, and strict — you can override any of those on top of it.

eslint.config.mjs

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({
  preset: Preset.App
})

Available Presets

Preset	Enum	Best For
Basic	Preset.Basic	Plain JavaScript projects with no TypeScript.
Node	Preset.Node	TypeScript packages running in Node.js (CLIs, scripts, APIs).
Browser	Preset.Browser	TypeScript apps running in the browser without a meta-framework.
Worker	Preset.Worker	Edge runtimes, service workers, and Cloudflare Workers.
Library	Preset.Library	Published npm packages — adds Prettier and tightens type-safety rules.
App	Preset.App	Browser applications — TypeScript + Prettier + Vitest by default.
CI	Preset.CI	Stricter severities for CI environments (warnings become errors).
Monorepo	Preset.Monorepo	Root config for workspace repositories with mixed project types.
All	Preset.All	TypeScript + every optional integration. Useful for audits and evaluation.

With the lean basic package, install the category packs selected by a preset. App uses Testing and Tools; Library, CI, and Monorepo use Extensions and/or Tools; All uses all five packs. Node, Browser, and Worker stay within the core + TypeScript boundary. The full package includes every preset dependency.

For an existing codebase, inspect the adoption delta before switching:

basic-eslint explain-preset app --file src/index.ts

Add --analyze-source to lint with the selected preset and run an in-memory autofix preview:

basic-eslint explain-preset app --analyze-source --file "src/**/*.{ts,tsx}"

Without --file, source analysis targets the whole project. The report groups current findings by rule, category, severity, file type, and fixability; calls out non-formatting errors to resolve first; and estimates which files and lines autofix would change. Fixable findings that remain after the preview are listed as potential fix conflicts. No source files are written.

Add --semantic-only to exclude formatting-rule fixes from the preview. Once that smaller report is reviewed, add --write to apply it. The CLI refuses source writes without semantic-only mode. The same analysis lists candidate file-reading scripts that use regular expressions, since those scripts may depend on quote or object-key formatting during a later formatting pass.

Add --compatibility to generate a temporary override for newly enabled rules. The report groups the delta by formatting, correctness, security, framework, and domain rules so migration work can be planned independently. Compatibility output preserves the current effective configuration; it does not suppress pre-existing source violations from rules that were already enabled.

What Each Preset Enables

Preset.Basic

The minimum viable config — core JavaScript rules only. No TypeScript, no runtime globals beyond ECMAScript standard. Use this as a base when you want full manual control over everything else.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({ preset: Preset.Basic })

Preset.Node

TypeScript enabled, Node.js globals active (process, __dirname, Buffer, etc.). Suitable for CLIs, build scripts, and server-side packages that run directly in Node.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({ preset: Preset.Node })

Preset.Browser

TypeScript enabled, browser globals active (window, document, navigator, etc.). Use for front-end code that does not use a full meta-framework — for example a vanilla TypeScript library or a standalone Vite project.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({ preset: Preset.Browser })

Preset.Worker

TypeScript enabled, service worker and Fetch API globals active (self, fetch, Request, Response, caches, etc.). Use for Cloudflare Workers, edge functions, or any runtime that matches the WinterCG API surface.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({ preset: Preset.Worker })

Preset.Library

TypeScript enabled, Prettier applied, strict type-safety rules tightened. Designed for packages you publish to npm where you want a consistent, well-typed public API and no leftover debug output.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({ preset: Preset.Library })

Preset.App

TypeScript enabled, browser globals, Prettier applied, Vitest included. The recommended starting point for any single-page application or web app — pair with a frameworks option to add React, Next.js, Vue, or another UI layer.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({
  frameworks: { next: true },
  preset: Preset.App
})

Preset.CI

Same as the project’s detected/explicit defaults, but with all warnings promoted to errors. Drop this into a CI-specific config or use it as your single config if you prefer zero-warning builds everywhere.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({ preset: Preset.CI })

[!TIP] Preset.CI is equivalent to setting strict: true — but using the preset keeps the intent explicit and readable.

Preset.Monorepo

Universal TypeScript defaults for a workspace root that lints many packages at once. Works best with the projects option so individual workspace packages can narrow their own preset and runtime.

import { defineConfig, Preset, Runtime } from '@santi020k/eslint-config-basic'

export default await defineConfig({
  preset: Preset.Monorepo,
  projects: {
    'apps/api': { preset: Preset.Node, runtime: Runtime.Node },
    'apps/web': { frameworks: { next: true }, preset: Preset.App }
  }
})

See the Monorepo guide for a full walk-through.

Preset.All

Enables TypeScript and every optional integration (all tools, libraries, testing frameworks, formats, and extensions). Intended for exploration and auditing — not recommended as a long-term production config because it includes integrations your project may not actually use.

With the lean basic package (or the compatibility lite package), Preset.All requires all five category feature packs. Modular projects usually get better dependency control by enabling only the specific features they need.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({ preset: Preset.All })

Presets and Frameworks

Presets do not activate framework configs. Frameworks come from auto-detection (enabled by default) or an explicit frameworks option. You can always add a frameworks key alongside any preset:

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({
  frameworks: { svelte: true },
  preset: Preset.Browser
})

Overriding Preset Defaults

Any explicit option you pass overrides the preset default for that field. List options (libraries, testing, formats, tools, extensions) are merged with preset defaults under optionMergeStrategy: 'merge' (the default). Use optionMergeStrategy: 'replace' when you want your explicit lists to fully replace what the preset provides.

Optional configs can be enabled with enum values, matching strings, or the features map. A features value of false removes that optional config after detection and preset defaults are merged.

import { defineConfig, Preset } from '@santi020k/eslint-config-basic'

export default await defineConfig({
  features: {
    prettier: false,
    zod: true
  },
  preset: Preset.App
})

Related Pages

• Configuration — full option reference
• Runtime — runtime enum values
• Monorepo — using presets across workspace packages