@typesugar/eslint-plugin

ESLint plugin that runs the typesugar macro transformer before linting.

This allows ESLint to see the expanded code, eliminating false positives from macro syntax like undefined identifiers in @derive(Eq, Clone).

Installation

npm install @typesugar/eslint-plugin --save-dev

Usage

Flat Config (ESLint 9+)

In your eslint.config.mjs:

import typesugarPlugin from "@typesugar/eslint-plugin";

export default [
  typesugarPlugin.configs.recommended,
  // ... your other configs
];

Full Transformation Mode

For more accurate linting with full macro expansion (slower):

import { fullConfig } from "@typesugar/eslint-plugin";

export default [
  fullConfig,
  // ... your other configs
];

Configurations

recommended

Lightweight pattern-based processing. Fast but may miss some macro expansions.

• Processes all .ts and .tsx files
• Disables rules that conflict with macro syntax (no-unused-labels, no-labels)

full

Uses the actual typesugar transformer for complete accuracy.

• Slower due to full TypeScript compilation
• Most accurate - sees exactly what TypeScript sees after transformation

strict

Extends recommended with additional checks.

How It Works

The plugin provides ESLint processors that transform your code before linting:

1. Lightweight mode: Pattern-based substitutions for common macro syntax
2. Full mode: Runs the complete typesugar transformer pipeline

This prevents false positives like:

• "Eq is not defined" from @derive(Eq, Clone)
• "Label 'requires' is unused" from contract blocks
• Type errors from un-expanded macro calls

API

clearTransformCache()

Clears the transformation cache. Useful in watch mode when you need to force re-transformation.

import { clearTransformCache } from "@typesugar/eslint-plugin";

clearTransformCache();

License

MIT