// Good - single source of truth const TAX_RATES: Record<string, number> = { CA: 0.0825, NY: 0.07 }; function calculateTotal(subtotal: number, state: string): number { return subtotal * (1 + TAX_RATES[state]); }


**G16: No Obscured Intent**

Don't be clever. Be clear.

```ts
// Bad - what does this do?
return ((x & 0x0f) << 4) | (y & 0x0f);

// Good - obvious intent
return packCoordinates(x, y);

G23: Prefer Polymorphism to If/Else

// Bad - will grow forever
function calculatePay(employee: {
  type: "SALARIED" | "HOURLY" | "COMMISSIONED";
  salary?: number;
  hours?: number;
  rate?: number;
  base?: number;
  commission?: number;
}): number {
  if (employee.type === "SALARIED") {
    return employee.salary ?? 0;
  } else if (employee.type === "HOURLY") {
    return (employee.hours ?? 0) * (employee.rate ?? 0);
  } else if (employee.type === "COMMISSIONED") {
    return (employee.base ?? 0) + (employee.commission ?? 0);
  }
  return 0;
}

// Good - open/closed principle
interface Employee {
  calculatePay(): number;
}

class SalariedEmployee implements Employee {
  constructor(private readonly salary: number) {}
  calculatePay(): number {
    return this.salary;
  }
}

class HourlyEmployee implements Employee {
  constructor(
    private readonly hours: number,
    private readonly rate: number,
  ) {}
  calculatePay(): number {
    return this.hours * this.rate;
  }
}

class CommissionedEmployee implements Employee {
  constructor(
    private readonly base: number,
    private readonly commission: number,
  ) {}
  calculatePay(): number {
    return this.base + this.commission;
  }
}

G25: Replace Magic Numbers with Named Constants

// Bad
if (elapsedTime > 86400) {
  // ...
}

// Good
const SECONDS_PER_DAY = 86400;
if (elapsedTime > SECONDS_PER_DAY) {
  // ...
}

G30: Functions Should Do One Thing

If you can extract another function, your function does more than one thing.

G36: Law of Demeter (Avoid Train Wrecks)

// Bad - reaching through multiple objects
const outputDir = context.options.scratchDir.absolutePath;

// Good - one dot
const outputDir = context.getScratchDir();

Enforcement Checklist

When reviewing AI-generated code, verify:

No duplication (G5)
Clear intent, no magic numbers (G16, G25)
Polymorphism over conditionals (G23)
Functions do one thing (G30)
No Law of Demeter violations (G36)
Boundary conditions handled (G3)
Dead code removed (G9)

clean-general

General Clean Code Principles

Critical Rules