Migration to v3

Version 3 changes the exhaustive preset contract so normal presets never enable deprecated rules implicitly.

Exhaustive preset changes

• etcMisc.configs.all now enables every non-deprecated rule with metadata-derived severities.
• etcMisc.configs.allStrict now enables every non-deprecated rule at error.
• etcMisc.configs.allWithDeprecated adds externally replaced or otherwise non-duplicated deprecated rules to all at warning severity.
• etcMisc.configs.allStrictWithDeprecated adds the same migration-only rules to allStrict at warning severity.

The deprecated-inclusive presets still omit deprecated rules with same-plugin replacements so overlapping implementations never execute together.

Deprecated rules remain exported in v3 for explicit migration use and advertise v4.0.0 as their likely removal version.

Migration

Most projects should keep their existing all or allStrict selection and accept the removal of deprecated diagnostics. If a staged migration requires the old behavior, temporarily switch to the matching deprecated-inclusive preset:

import etcMisc from "eslint-plugin-etc-misc";

export default [etcMisc.configs.allWithDeprecated];

Remove deprecated rule violations and then return to all or allStrict.

Rule ownership changes

Version 3 narrows this package to rules that provide distinct behavior. The following maintained projects now own behavior that was duplicated here:

Deprecated rule family	Replacement
default-case, no-writeonly	ESLint core default-case, accessor-pairs
consistent-empty-lines	@stylistic/no-multiple-empty-lines
Array, object, export, and interface-member sorting rules	Perfectionist and @typescript-eslint/member-ordering
no-implicit-any-catch	@typescript-eslint/use-unknown-in-catch-callback-variable
no-misused-generics	@typescript-eslint/no-unnecessary-type-parameters
throw-error	@typescript-eslint/only-throw-error and @typescript-eslint/prefer-promise-reject-errors
no-unnecessary-template-literal	unicorn/no-useless-template-literals
restrict-identifier-characters, no-underscore-export	ESLint core id-match, no-restricted-exports
typescript/no-complex-return-type	@typescript-eslint/explicit-function-return-type

The four jsx-no-*-as-prop rules are replaced by the broader local no-unstable-react-values rule. It remains opt-in because React Compiler makes blanket identity-stability linting a poor general default.

Readonly rule ownership

Use @typescript-eslint/prefer-readonly for mutation-aware private class state and @typescript-eslint/prefer-readonly-parameter-types for deep parameter analysis. When migrating existing annotations, enable checkParameterProperties, set ignoreInferredTypes according to the desired strictness, and set treatMethodsAsReadonly: true when ReadonlyMap and ReadonlySet should satisfy the policy.

The plugin retains its non-parameter collection rules for property, return, and type-alias annotations, plus typescript/prefer-readonly-index-signature. The broad collection rules and parameter-only rules are deprecated because they overlapped those retained rules and typescript-eslint.

Correctness changes

• no-unnecessary-initialization no longer reports const declarations, because removing a const initializer creates invalid JavaScript.
• Deprecated no-unnecessary-template-literal ignores tagged templates so its fixer cannot change tagged-template syntax into invalid code.
• Deprecated typescript/define-function-in-one-statement reports only direct property assignments on locally declared function values instead of every member assignment.
• typescript/prefer-enum is deprecated because it contradicted no-enum in exhaustive presets.

Verification

Inspect the effective flat config and run the repository lint suite after upgrading:

npx eslint --print-config path/to/file.js
npx eslint .