LowFile-scopeJavaScript / TypeScript Plug & play

Derive TypeScript types from validation schemas

Avoid duplicating runtime schemas and TypeScript types; derive types from constants/functions or declare as const tuples.

Why this matters

Keeps types and runtime in sync, reducing drift.

Side-by-side examples engineers can pattern-match during review.

Avoid

type Status = 'syncing'|'synced'|'error'; const STATUSES=['syncing','synced','error'];

Prefer

const STATUSES = ['syncing','synced','error'] as const; type Status = typeof STATUSES[number];

Bad

type X='a'|'b'; const ARR=['a','b']

Good

const ARR=['a','b'] as const; type X=typeof ARR[number]

From the same buckets as this rule.

Critical
Avoid Duplicating String Literals
Store repeated string literals in constants or variables to improve maintainability and reduce redundancy.
duplication-complexitymaintainability
Critical
Avoid Redundant `None` Comparisons
Identify cases where `x is None` or `x is not None` is used redundantly when `x` is always or never `None`. This may indicate a deeper logic issue.
duplication-complexityreadability-refactor+1
High
Avoid Functions That Always Return the Same Value
Identify functions that return the same value regardless of input. This may indicate poor design or a logic error.
duplication-complexityreadability-refactor+1