config-best-practices-review

Configuration & Best Practices Review (November 2025)

Project: chatline

Scope covered: TypeScript (build & emit), ESM packaging, Exports strategy, Vitest, Coverage, ESLint (flat config), Prettier, Changesets, Release hygiene, CLI delivery, Automation opportunities (Firecrawl).

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1. Executive Summary

The project already aligns with many 2025 best practices: strict TypeScript settings, modern flat ESLint config, Vitest with thread pool limits, CI specific reporters, and a lean published surface. Remaining gaps revolve around polishing ESM publish ergonomics, strengthening coverage enforcement, import/order consistency, and automating config drift detection (future Firecrawl integration).

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2. Current State Snapshot

Area	Current	Notes
Module format	Pure ESM ("type": "module")	Single root export only
Export map	Root export + types	No subpath exports, no package.json export
Declarations	declaration: true, source maps	No declarationMap yet
TS target	ES2022, moduleResolution: bundler	Good for modern Node + bundlers
Strictness	strict, exactOptionalPropertyTypes, noUncheckedIndexedAccess	Strong correctness posture
Vitest env	jsdom, threads pool (max 8)	Good isolation & concurrency control
Coverage	Global thresholds (70%)	No all: true, no per‑file thresholds
ESLint	Flat config, type aware segment	Good layering; lacks import ordering
Formatting	Prettier with granular overrides	Extensive, may be simplified later
Changesets	Config present, repo points to old name	Needs repo update
CLI	Shebang in source TS	Need to ensure preserved post build
Supply chain	provenance: true, minimal files list	Add CHANGELOG, sideEffects flag

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3. Strengths

1. Robust TypeScript strictness (edge cases like optional property correctness & unchecked index access covered).
2. Flat ESLint config with targeted type-aware rules reduces lint cost for non-TS files.
3. Vitest concurrency tuned (threads capped) + CI aware reporters and output paths.
4. Minimal publish surface (files whitelist) aids consumer install size & security.
5. Provenance publishing set, improving supply chain trust.
6. Path alias parity between TS and Vitest ensures consistent imports.

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4. Gaps / Risks

Gap	Impact	Category
Missing declarationMap	Slightly reduced consumer DX	Types
Missing sideEffects: false	Leaves tree-shaking optimization implicit	Packaging
No ./package.json export entry	Some tooling resolution gaps	Packaging
Coverage not enforcing all & per-file	Untested files invisible to quality gate	Testing
Lack of import order rule	Inconsistent diffs / churn	Lint consistency
Shebang may be stripped by tsc	Potential CLI execute failure if lost	Distribution
Outdated Changesets repo reference	Changelog links misdirect	Release
No explicit testTimeout	Potential hidden hanging tests	Testing
Not using newer TS features (verbatimModuleSyntax, declarationMap)	Slight DX loss	TypeScript
No automation for config drift	Manual effort to monitor ecosystem changes	Maintenance

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5. Recommended Improvements (Prioritized)

High Priority

1. Add to package.json: "sideEffects": false, export for ./package.json.
2. Enable declarationMap: true + verbatimModuleSyntax: true in tsconfig.base.json.
3. Strengthen coverage: coverage.all: true, raise per-file thresholds (lines/statements 80, branches 75, functions 80) & enable perFile: true.
4. Preserve CLI shebang: confirm tsconfig has preserveShebang: true (TS 5.4+), or introduce a tiny wrapper script.
5. Update .changeset/config.json repo reference to nathanvale/chatline.

Medium Priority 6. Introduce eslint-plugin-import with import/order alphabetical + groups. 7. Add testTimeout (e.g. 20_000 ms) & optionally hookTimeout. 8. Add coverage.dependantData: true (when Vitest adds stable support) to improve branch accuracy (future looking). 9. Add script: "typecheck": "tsc -p tsconfig.eslint.json --noEmit".

Low Priority / Optional 10. Add subpath exports if you decide to expose internal modules. 11. Add lint-staged + pre-commit optimization. 12. Implement Firecrawl-based config drift job (see Section 9).

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6. Concrete Snippet Proposals

package.json (additions excerpt):

{
  "sideEffects": false,
  "exports": {
    ".": { "import": "./dist/index.js", "types": "./dist/index.d.ts" },
    "./package.json": "./package.json",
  },
}

tsconfig.base.json (compilerOptions additions):

{
  "compilerOptions": {
    "declarationMap": true,
    "verbatimModuleSyntax": true,
    "preserveShebang": true,
  },
}

vitest.config.ts (inside test.coverage):

coverage: {
  provider: 'v8',
  all: true,
  reporter: process.env.TF_BUILD ? ['text-summary','html','lcov'] : ['text-summary','html'],
  reportsDirectory: process.env.TF_BUILD ? './test-results/coverage' : './coverage',
  exclude: ['src/**/*.d.ts','**/*.test.*','dist/**','vitest.config.*'],
  thresholds: { lines: 80, statements: 80, branches: 75, functions: 80, perFile: true },
}

ESLint import ordering layer (flat config fragment):

import importPlugin from 'eslint-plugin-import'

export default [
  // existing config blocks ...,
  {
    name: 'project/imports',
    plugins: { import: importPlugin },
    rules: {
      'import/order': [
        'warn',
        {
          alphabetize: { order: 'asc', caseInsensitive: true },
          'newlines-between': 'always',
          groups: [
            'builtin',
            'external',
            'internal',
            'parent',
            'sibling',
            'index',
            'object',
            'type',
          ],
        },
      ],
    },
  },
]

CLI wrapper alternative (if not using preserveShebang):

#!/usr/bin/env node
import('../dist/cli.js')

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7. Validation / Edge Considerations

Area	Edge Case	Mitigation
Shebang	Build strips comment	Add preserveShebang or wrapper
SideEffects flag	Hidden global code (e.g. polyfills)	Audit entrypoints before enabling
Coverage all	Large new modules drop %	Enforce incremental discipline
Import ordering	Large diff churn on first run	Communicate in PR description
Subpath exports	Breaking consumers expecting deep requires	Mark as new minor version

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8. Roadmap (Suggested Sequence)

1. Packaging polish (sideEffects, declarationMap, shebang preservation).
2. Coverage strengthening.
3. Import order + type safety rule expansion.
4. Changesets repo correction & add CHANGELOG to files.
5. Firecrawl automation.

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9. Firecrawl / Viacrawl Automation Plan

1. Curate authoritative doc URLs (ESLint flat config, TypeScript release notes, Vitest advanced docs, Node ESM guide).
2. Use Firecrawl map + scrape to harvest markdown snapshots.
3. Extract structured config guidance (simple heuristics: fenced JSON, tables referencing options) into a local store (JSON lines).
4. Parse local project configs into AST (e.g. via typescript + lightweight custom walkers for export default [...]).
5. Diff recommended vs actual (rule missing, threshold below recommendation, option deprecated) and emit docs/config-drift.md.
6. Gate CI with a script: fails if drift severity > defined threshold.
7. (Optional) Use embeddings to cluster new guidance and open an automated PR with proposed config deltas.

Success Criteria:

• Drift job produces deterministic output within < 5s warm run.
• No false positives > 5% over a rolling 30‑day window.

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10. Quick Win Checklist

• Add sideEffects flag
• Add declarationMap + verbatimModuleSyntax
• Preserve CLI shebang
• Strengthen coverage config
• Update Changesets repo
• Add import/order lint layer
• Add typecheck script
• Implement drift automation (post Firecrawl activation)

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11. Optional Enhancements

Enhancement	Benefit
Subpath exports	Granular consumer imports, potential tree-shake improvements
lint-staged	Faster pre-commit feedback
Security scan (Scorecards)	Supply chain confidence
Per-module API docs (TS Doc + typedoc)	Consumer onboarding

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12. Summary

The configuration foundation is solid and future-forward. Implementing the prioritized set (Sections 5 & 8) will close remaining polish gaps around packaging clarity, coverage rigor, and automation. Firecrawl can later provide a sustainable feedback loop to keep configurations aligned with evolving ecosystem guidance.

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Generated: 2025-11-11