implement-command

# Implement Command Use this skill when adding a missing Redis command, correcting an existing command signature, changing command return types, or adding coverage for command-specific Buffer, callback, pipeline, or transformer behavior. ## Command Support Map - `@ioredis/commands`: upstream command metadata consumed by the generator. - `bin/index.js`: generator entry point for `lib/utils/RedisCommander.ts`. - `bin/returnTypes.js`: command return type map. Most new commands need an entry here. - `bin/argumentTypes.js`: command-specific argument shape overrides when metadata or global mapping is insufficient. - `bin/typeMaps.js`: global Redis argument category to TypeScript type mapping. - `bin/overrides.js`: manual overloads for signatures the generator cannot express cleanly. - `bin/sortArguments.js`: argument reordering for commands whose generated order is wrong. - `lib/utils/RedisCommander.ts`: generated declarations. Regenerate it; do not hand-edit it. - `lib/Command.ts`: command argument and reply transformer registry. Touch only when transformer behavior is needed. - `test/functional/commands/<command>.ts`: runtime command coverage. - `test/functional/transformer.ts`: transformer runtime coverage. - `test/typing/commands.test-d.ts`: public command typing coverage. - `test/typing/transformers.test-d.ts`: transformer typing coverage. ## Workflow 1. Establish command scope. - Normalize command keys to lowercase, matching `bin/returnTypes.js`. - Resolve command aliases or subcommands before editing. - Confirm the command exists in `@ioredis/commands`. If it is missing there, stop and report that the metadata package must be updated before ioredis can generate typed command support. - Identify the minimum Redis server version needed and whether functional tests must be version-gated. 2. Inspect current support. - Search `lib/utils/RedisCommander.ts`, `bin/`, `test/functional/commands/`, and `test/typing/` for the command and related aliases. - Inspect nearby command families before choosing types, for example hash expiration commands, sorted-set commands, stream commands, or pub/sub commands. - Check existing argument and reply transformers before adding new ones. 3. Update generator inputs. - Prefer `bin/returnTypes.js` for return type corrections. - Use a string return type for simple fixed replies. - Use a function return type when replies depend on subcommands, options, or tokens. - Reuse `hasToken` and `matchSubcommand` in `bin/returnTypes.js` when they fit. - Use `bin/argumentTypes.js` only for command-specific argument overrides. - Use `bin/typeMaps.js` only for broad metadata category fixes that should affect multiple commands. - Use `bin/overrides.js` only when generated overloads cannot express the supported API cleanly. - Keep command names lowercase in generator maps unless the surrounding file uses another established convention. 4. Regenerate declarations. - In this repo, use `node bin/index.js` unless `package.json` later adds an explicit generation script. - Review the generated diff in `lib/utils/RedisCommander.ts`. - Check the normal method, callback overload, pipeline/transaction shape, and Buffer variant when the command returns strings, arrays, nullable bulk replies, or transformed objects. - If generation changes unrelated commands, inspect the generator input and do not accept surprising churn without an explanation. 5. Add focused runtime coverage. - Put command tests in `test/functional/commands/<lowercase-command>.ts`. - Use `import Redis from "../../../lib/Redis";` and `import { expect } from "chai";`. - Prefer `let redis: Redis`, `beforeEach(() => { redis = new Redis(); })`, and `afterEach(() => { redis.disconnect(); })`. - For version-gated command tests under `test/functional/commands/`, import `isRedisVersionLowerThan` from `../../helpers/util`, and use `before(async function () { ... this.skip(); })`; use function syntax when calling `this.skip()`. - Use unique keys such as `${command}_${caseName}_${Date.now()}`. - Test the ioredis command surface: accepted argument shapes, option ordering, callback behavior, Buffer variants, and reply shape. - Keep assertions focused on what ioredis sends and returns. Do not test Redis server internals beyond the smallest deterministic setup needed. - Assert exact replies when stable; otherwise assert primitive type, nullable behavior, array/object shape, or Buffer conversion. 6. Add typing coverage when useful. - Add cases to `test/typing/commands.test-d.ts` when the command has nontrivial overloads, return types, Buffer variants, callback typing, or option-dependent replies. - Cover `expectType<Promise<...>>(redis.command(...))`. - Add Buffer variant expectations when the command has one. - Add callback typing for nontrivial return types. - Use `expectError` only for meaningful invalid signatures. - Update `test/typing/transformers.test-d.ts` only when transformer APIs are affected. 7. Consider documentation. - Use the repo `docs-sync` skill when command support changes public signatures, return mapping, examples, or documented command behavior. - Usually command support is documented through generated declarations and typing tests; update README/docs only when existing prose or examples cover the affected command family or users need version/topology caveats. 8. Validate. - Run `node bin/index.js` after generator input changes. - Run the focused functional command test when Redis support is available, using the repo's Mocha pattern with `test/helpers/*.ts`. - Run `npm run build` when generated declarations, public TypeScript, or generator output changed. - If typing tests changed, run `npx tsd --files test/typing/commands.test-d.ts` after building. - Use the repo `code-change-verification` skill before handoff to choose any additional validation. - If Redis access is blocked by sandboxing, ask for permission to access the local Redis server rather than assuming it is unavailable. ## Completion Report Report: - Commands added or updated. - Metadata/generator inputs changed. - Generated files changed. - Functional tests added or updated. - Typing tests added or updated. - Documentation decision. - Validation commands run and results. - Skipped validation with the concrete reason, including Redis version or local environment limits.