productive-eslint/docs/configuration.md

Mildly strict and sufficiently practical ESLint config based on Evgeny Orekhov's eslint-config-hardcore

# Configuration Model

The public entry point is `createConfig(options)`.

```ts
import { createConfig, Preset } from 'productive-eslint'

export default createConfig({
  preset: Preset.RECOMMENDED,
})
```

## Presets

`Preset.AUTO_FIXABLE` enables rules with reliable ESLint autofix support.

`Preset.RECOMMENDED` is the default permanent baseline. It includes
`AUTO_FIXABLE` and adds mechanical non-autofixable rules that should not require
human design judgment.

```mermaid
flowchart LR
  auto[Preset.AUTO_FIXABLE] --> recommended[Preset.RECOMMENDED]
  recommended --> baseline[Permanent lint baseline]
```

## Config Composition

Each plugin config exports a preset map with two keys:

- `autoFixable`
- `recommended`

`mergePresetConfigs(map, preset)` composes these layers in order.

```mermaid
flowchart TD
  factory[createConfig] --> options[Resolve options]
  options --> autoDetect[Detect Vue and RxJS when not explicit]
  autoDetect --> presetMerge[mergePresetConfigs per rule family]
  presetMerge --> composer[FlatConfigComposer]
  composer --> marker[Runtime productive-eslint marker]
```

The runtime marker is important for the CLI. It lets analyzers verify that the
target project uses a supported `productive-eslint` composer pipeline rather
than an arbitrary ESLint config shape.

## Vue and RxJS

Vue and RxJS support can be enabled explicitly:

```ts
export default createConfig({
  rxjs: true,
  vue: true,
})
```

If an option is omitted, `productive-eslint` tries to detect the package in the
current project. In monorepos, explicit options are usually clearer when the
shared ESLint wrapper is used by many package roots.

## Permanent Rules vs Analyzer Rules

Permanent rules should be safe to run during ordinary development. Analyzer
rules are intentionally stronger and more contextual because they are used only
for explicit review commands.

```mermaid
flowchart TD
  rule[Potential ESLint rule] --> question{Mechanical and local?}
  question -->|Yes| permanent[Permanent preset]
  question -->|No| analyzer[On-demand analyzer]

  permanent --> lint[eslint .]
  analyzer --> review[productive-eslint analyze topic]
```