Summary

The generated TypeDoc documentation strips | null from every command that can return null. For example, redis.get() is rendered as Promise<string> even though its declared signature is Promise<string | null>. The same issue affects 70+ commands across Redis, Cluster, and ChainableCommander (e.g. get, getex, getdel, mget, hmget, zscore, zrank, bzpopmin, blpop, lpop, spop, geopos, ...).

Root cause

strictNullChecks is off in tsconfig.json. With it disabled, TypeScript treats null as assignable to every type, so string | null collapses to string during type resolution. TypeDoc reads the collapsed type from the compiler and renders it as Promise<string>.

Fix

Generate docs with strictNullChecks enabled, without affecting the main build:

1. Add tsconfig.docs.json that extends tsconfig.json and sets strictNullChecks: true.
2. Update the docs script to pass --tsconfig ./tsconfig.docs.json and --skipErrorChecking (existing source has pre-existing strictNullChecks violations that are unrelated to docs generation).
3. Bump typedoc from ^0.22.18 to ^0.25.13. 0.25 is the newest TypeDoc line that still supports TypeScript 4.6.x, and it's the minimum version providing --skipErrorChecking.

No runtime code, build output, or public type declarations are changed.

Before / after

redis.get(key) signature in docs/classes/Redis.html:

• Before: get(key, callback?): Promise<string>
• After: get(key, callback?): Promise<null | string>

The same correction applies to all nullable-return commands