list-toolkit — AI Agent Rules

<!-- Canonical source: AGENTS.md — keep this file in sync -->
# list-toolkit — AI Agent Rules

> `list-toolkit` is a zero-dependency ESM JavaScript library providing list-based data structures. Works in Node.js, Bun, Deno, and browsers.

For project structure, core concepts, and the module dependency graph see ARCHITECTURE.md.
For detailed usage docs and API references see the wiki.

## Verification commands

- `npm test` — run the full test suite (tape-six)
- `node tests/test-<name>.js` — run a single test file directly
- `npm run test:bun` — run with Bun
- `npm run test:deno` — run with Deno
- `npm run ts-check` — TypeScript type checking (tsc --noEmit)
- `npm run ts-test` — run TypeScript typing tests (Node)
- `npm run lint` — Prettier format check
- `npm run lint:fix` — Prettier auto-format

## Writing tests

Tests use tape-six. For the full testing API, patterns, and conventions see `node_modules/tape-six/TESTING.md`.

## Critical rules

- **ESM-only.** `'use strict'` is not used; the project is `"type": "module"`.
- **No runtime dependencies.** Never add packages to `dependencies`. Only `devDependencies` are allowed.
- **Do not modify or delete test expectations** without understanding why they changed.
- **Do not add comments or remove comments** unless explicitly asked.

## Code style

- Prettier: 160 char width, single quotes, no bracket spacing, no trailing commas, arrow parens "avoid" (see `.prettierrc`).
- 2-space indentation (`.editorconfig`).
- Imports at top of file. No dynamic imports unless necessary.

## When reading the codebase

- Start with ARCHITECTURE.md for the module map and dependency graph.
- Wiki markdown files in `wiki/` contain detailed usage docs and API references.
- `list/nodes.js` and `slist/nodes.js` are the foundational modules — read them first to understand the class hierarchy.