typescript-strictness-mining

Read-only mining plus an optional migration workflow for TypeScript strictness in any repository layout — monorepos (apps/, packages/, libs/, src/, etc.) or single-package projects.

Registry package: typescript-strictness-mining

Use mining for dashboards and prioritization. Use migration only when you intend to change code.

Quick start

From your project root:

bash
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# Read-only mining (default workflow)
npx codemod run typescript-strictness-mining -t . --dry-run

# Apply migration (writes files — review the diff first)
npx codemod run typescript-strictness-mining --workflow migration -t . --allow-fs --dry-run

Use -t /path/to/repo to scan a directory other than the current one. Drop --dry-run when you are ready to apply changes.

Codemod Insights

To visualize findings in a dashboard:

1. Go to app.codemod.com/insights
2. Create a dashboard and widget
3. Set the source to js-ast-grep and select typescript-strictness-mining from the registry

Metrics appear in the run report and in Insights widgets keyed on strictness-finding and strictness-package-readiness.

Scope

The codemod scans from the path you pass with -t:

• Source: **/*.{ts,tsx,mts,cts,js,jsx,mjs,cjs} (standard build/output dirs excluded)
• Config: **/tsconfig.json only — not tsconfig.app.json, tsconfig.build.json, or other variants

Monorepo layouts such as apps/ / packages/ work out of the box. No Turborepo- or vendor-specific paths are required.

When compilerOptions.strict is fully enabled with no disabled strict flags, config mining emits no finding for that package.

Antipattern reference

Syntax (default mining workflow)

Config (default mining workflow)

Config findings are emitted during the config scan only. The compiler readiness step does not duplicate them.

Compiler (opt-in mining or migration workflow)

Parameters

Pass with --param key=value on the CLI, or edit fields in Codemod Insight when running from the UI.

Mining workflow (default)

Migration workflow (--workflow migration)

Metrics

strictness-finding

Per-occurrence findings. Cardinality fields: file, line, antipatternType, sourceKind, fixability, suggestedAction, confidence, optional diagnosticCode.

strictness-package-readiness

Once per tsconfig.json. Cardinality fields: packageName, packagePath, readiness (ready | blocked), strictState, blockingBucket, optional partialFlags.

Emitted only when the compiler readiness step runs — not on default mining (syntax + config only).

What each workflow does

Mining (default)

1. Syntax scan — as any, !, @ts-*, : any (and optional index access).
2. Config scan — tsconfig strictness state per package.
3. Compiler scan (optional, includeCompilerFindings=true) — tsc blockers and package readiness rollups.

Default mining avoids a full tsc pass on every file for speed. Compiler findings are opt-in or use the migration workflow.

Migration (--workflow migration)

1. Compiler readiness — tsc blockers and package readiness rollups (skips or marks packages blocked when a project is too large or tsc fails).
2. Safe-fix — deterministic edits only when each change passes strict tsc (project-scoped when a tsconfig.json is found) and a syntax check:
   • removes stale // @ts-expect-error together with a paired eslint-disable-next-line @typescript-eslint/ban-ts-comment when present (never @ts-ignore / @ts-nocheck)
   • removes as any / <any> when safe (skips bracket-index casts and (x as any).prop member-access casts)
   • does not auto-remove ! (non-null assertions) — leave those to mining + AI/manual cleanup
3. Enable strict (optional, enableStrictIfReady=true) — sets strict: true when blockers are zero.
4. AI cleanup — runs by default (runAiCleanup=true); pass --param runAiCleanup=false for deterministic-only runs.

Migration may read files from disk (--allow-fs).

Examples

bash
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# Read-only mining on the current directory
npx codemod run typescript-strictness-mining -t . --dry-run

# Mining on another repo
npx codemod run typescript-strictness-mining -t /path/to/repo --dry-run

# Include high-volume index-access findings
npx codemod run typescript-strictness-mining -t . \
  --param includeUnsafeIndexAccess=true \
  --dry-run

# Mining + compiler blockers + readiness rollups
npx codemod run typescript-strictness-mining -t . \
  --param includeCompilerFindings=true \
  --allow-fs \
  --dry-run

# Migration — deterministic steps only (no AI)
npx codemod run typescript-strictness-mining --workflow migration -t . \
  --param targetPackageGlob=packages/foo \
  --param runAiCleanup=false \
  --allow-fs \
  --dry-run

# Migration — enable strict when ready
npx codemod run typescript-strictness-mining --workflow migration -t . \
  --param enableStrictIfReady=true \
  --param runAiCleanup=false \
  --allow-fs \
  --dry-run