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eslint-plugin-configs

@anchildress1/awesome-github-copilot
42
22

Generate or update an ESLint plugin that exports rule configs compatible with ESLint v8 (eslintrc) and ESLint v9 (flat config).

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$npx skills-installer add @anchildress1/awesome-github-copilot/eslint-plugin-configuring --client shared
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Writes to .agents/skills.

$npx skills-installer add @anchildress1/awesome-github-copilot/eslint-plugin-configuring -p --client shared
Note: Review the skill instructions before using it.

SKILL.md

status draft
name eslint-plugin-configuring
description Generate or update an ESLint plugin that exports rule configs compatible with ESLint v8 (eslintrc) and ESLint v9 (flat config).

Stale target. Rules below cover ESLint v8 and v9. v9 reached end-of-life 2026-08-06; v10 has been current since February 2026 and dropped Node < 20.19. Confirm the consumer's ESLint major and check https://eslint.org/docs/latest/extend/plugins for v10 plugin-shape changes before applying anything. Never assume the v9 shapes still hold.

Scope: author or modify an ESLint plugin package exporting rules, configs (flat and/or legacy), optional processors, and meta (name, version, namespace). Deliverable is plugin source plus working consumer examples.

File Use for
references/eslint-plugin-configs.md Plugin skeleton and config-assignment code
examples/consumers.md Flat and legacy consumer configs for each naming strategy

Version semantics — state these correctly or not at all

Version Default Other mode
v9 Flat config .eslintrc* deprecated; applies only with ESLINT_USE_FLAT_CONFIG=false
v8 .eslintrc* Flat opt-in via eslint.config.js or ESLINT_USE_FLAT_CONFIG=true

Hard constraints

  • Never claim a plugin can force its own config to be used. It cannot.
  • Never invent config-resolution behavior that isn't documented.
  • Never mix flat and legacy shapes: no flat object exported as legacy, no legacy config exported as an array.
  • Never emit colliding or ambiguous config names.
  • Never silently rename or remove a published config key — breaking for every consumer.

Inputs (assume derivable)

PACKAGE_NAME · NAMESPACE (rule/config prefix) · RULES (ruleId → implementation) · desired config set (recommended, strict, …).

Plugin shape

Single object, ESM default export:

  • meta — name, version, namespace
  • rules
  • configs
  • processors (optional)

meta.namespace is the canonical prefix for rules, configs, and registration. Rule IDs inside the plugin never contain /. Every rule reference in a config is "<namespace>/<ruleId>".

Naming strategy — pick one, apply throughout

Strategy When Keys
A (default) New plugin, or you own the public API Flat flat/<configName> · Legacy legacy-<configName>
B Legacy <configName> already published Keep <configName> exactly; add flat/<configName>

Config requirements

Flat (v9 primary) — array of config objects · plugin registered in object form plugins: { [namespace]: plugin } · namespaced rule keys · languageOptions optional. configs["flat/recommended"] → Array<FlatConfigObject>

Legacy (v8) — plain eslintrc object · plugins: ["<namespace>"] · namespaced rule keys · globals/parserOptions optional. configs["legacy-recommended"] → EslintrcObject

Self-reference

A config that references the plugin object must not read plugin before it exists:

  1. Create plugin with configs empty.
  2. Assign configs afterward (Object.assign).

Consumer mapping

The flat/ prefix is an export key, never a consumer string.

Export key Consumer extends
configs["flat/recommended"] "namespace/recommended"
configs["legacy-recommended"] "namespace/legacy-recommended"
configs["recommended"] (Strategy B) "namespace/recommended"

Required output

Unless the user excludes them, emit both, matching the chosen naming strategy exactly:

  1. Flat — eslint.config.js, using defineConfig, registering the plugin, using extends.
  2. Legacy — .eslintrc (JSON/YAML/JS), using plugins + extends.

Plus plugin source or diffs, and the validation result below.

Migration

  • Legacy only, dual support wanted → add flat/<name>
  • Flat only, v8 support wanted → add legacy-<name>
  • meta.namespace missing → add it and realign every rule prefix
  • Consumer examples disagree with config keys → regenerate the examples, not the keys

Validation gate

All must hold before reporting done:

  • meta.name, meta.version, meta.namespace present; namespace matches every rule prefix
  • Flat configs are arrays and register via object form
  • Legacy configs are eslintrc-shaped and register via array form
  • One naming strategy applied throughout; no config key collisions
  • Version behavior stated correctly per the table above
  • No claim that the plugin forces config usage