core-typescript-as-any

What it catches

as any type assertions in TypeScript source. Word-bounded match — variables / functions named anyway, anything, etc. are not flagged. String literals and comments are stripped before matching so docs mentioning the pattern don't fire.

Why it matters

as any tells TypeScript to drop every check on the expression. The compile-time guarantee that protects every downstream usage of this value silently disappears. AI coding tools reach for as any as their default escape hatch when the type system pushes back; left unflagged, the codebase accumulates them until removing one becomes a 50-file refactor.

Example: failing code

export function loadUser(raw: unknown): User {
  return raw as any;                       // MAJOR
}
export function processList(items: unknown[]): User[] {
  return items as any[];                   // MAJOR
}

Example: how to fix

Pick the narrowest replacement that compiles:

// (a) Local type + structural check (preferred)
export function loadUser(raw: unknown): User {
  const r = raw as { id?: unknown; email?: unknown };
  if (typeof r?.id !== 'string' || typeof r?.email !== 'string') throw new Error('bad shape');
  return { id: r.id, email: r.email };
}

// (b) Runtime validator (zod / valibot / ajv) — best for external input
import { z } from 'zod';
const UserSchema = z.object({ id: z.string(), email: z.string().email() });
export function loadUser(raw: unknown): User {
  return UserSchema.parse(raw);
}

// (c) Module declaration to fix wrong third-party types
// types/some-library.d.ts:
// declare module 'some-library' { export function f(x: number): string; }

Severity by file context

Test fixture paths (/tests/, /__tests__/, /spec/, *.test.ts, etc.) get a one-step downgrade to MINOR + confidence 0.6 — as any in tests is usually pragmatic shimming, not production risk.

Known limitations

• Doesn't detect the deprecated angle-bracket form <any>x. v1.1 AST pass will.
• Doesn't catch as any as Foo chains specifically; the first as any is flagged.

Suppression

// codemore-ignore-next-line: core-typescript-as-any
const sneakyButNecessary = thirdPartyMisTyped as any;

Or for an entire file:

/* codemore-ignore-file: core-typescript-as-any */

References

• TypeScript Handbook — Type assertions
• TypeScript ESLint — no-explicit-any