Guidance for configuring JavaScript and TypeScript code-quality tools such as ESLint, Prettier, Stylelint, PostCSS, and Svelte.

Use it when editing tool configuration, adding or removing linting plugins, checking formatter conflicts, or reviewing the JavaScript and TypeScript toolchain.

It helps you decide which configuration packages are needed and resolve conflicts between tools that check or format code.

js-config — Skill for Claude Code by fubits1/svelte-skills

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent

npx skills add fubits1/svelte-skills --skill js-config

Clone the repo

git clone --depth 1 https://github.com/fubits1/svelte-skills

Made for: Claude Code.

Or install frontend, the plugin that ships this one along with the rest of its 13 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

README.md

[![agentmods](https://agentmods.dev/badge/skills/fubits1/svelte-skills/js-config/github.svg)](https://agentmods.dev/skills/fubits1/svelte-skills/js-config)

Your own site

<a href="https://agentmods.dev/skills/fubits1/svelte-skills/js-config"><img src="https://agentmods.dev/badge/skills/fubits1/svelte-skills/js-config/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

Your own site · 80×15

<a href="https://agentmods.dev/skills/fubits1/svelte-skills/js-config"><img src="https://agentmods.dev/badge/skills/fubits1/svelte-skills/js-config.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 860 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin original No closer match found in the catalogue.

Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

Model	Per session	Once invoked
Fable 5.1	$0.00055	$0.00860
Opus 5.5	$0.00022	$0.00344
Sonnet 5.5	$0.00011	$0.00172
Haiku 4.5	$0.00006	$0.00086

Measured 2mo ago against content hash 66c8cebb7a56, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

js-config scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2mo ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/frontend/skills/js-config/SKILL.md · 87 lines

How it starts

The opening of the file, as written. The whole thing — 87 lines — stays where its author put it; the contents beside it link to each section on GitHub.

JS Config

Actionable decisions for JS/TS toolchain configuration.

ESLint + Prettier: What To Do

Scenario: ESLint and Prettier conflict on formatting

Run pnpm exec eslint-config-prettier src/some-file.js
If conflicts found, add eslint-config-prettier. See eslint-prettier.md for flat config setup.
If no conflicts, ESLint config has no formatting rules. Nothing to fix.

Scenario: Should I add/keep `eslint-config-prettier`?

Only needed if ESLint has active formatting rules (indent, quotes, semi, comma-dangle, etc.)
Modern recommended configs enable zero formatting rules
Legacy configs (airbnb, standard) enable many, so you need it
Verify: pnpm exec eslint-config-prettier src/some-file.js

Scenario: Knip/audit flags `eslint-config-prettier` as unused

If not imported in eslint.config.js, it has zero effect. Safe to remove.
If imported but CLI checker finds no conflicts, safe to remove.

Three different packages: know which is which

Package	What it does	When to use
`eslint-config-prettier`	Turns OFF ESLint formatting rules that clash with Prettier	When ESLint config has formatting rules active
`eslint-plugin-prettier`	Runs Prettier inside ESLint as a linting rule	Rarely, slower, worse editor DX. Prefer running Prettier separately.
`svelte.configs.prettier`	Built into `eslint-plugin-svelte`, turns off Svelte-specific formatting rules	When using eslint-plugin-svelte with Prettier

Full research, flat config code examples, and sources: eslint-prettier.md

Svelte Config vs Vite Config vs Astro Config

Three config files touch Svelte/Vite behavior. Know which one owns what.

File	What goes here	NOT here
`svelte.config.js`	Svelte compiler options, preprocessors (`vitePreprocess`), inspector toggle	Vite plugins
`astro.config.mjs` under `vite.plugins`	Vite plugins that transform imports (SVG-as-component, YAML, devtools)	Svelte compiler options
`vite.config.js`	Only in pure Vite/SvelteKit projects. Astro owns Vite config via `astro.config.mjs`

Read the full file on GitHub · 87 lines

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

eslint-prettier.md 6.5 KB

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

2mo ago First seen · 87 lines · 55 tokens per session scan A 66c8cebb7a56

Subscribe to this mod's changes

js-config is a skill published in the GitHub repository fubits1/svelte-skills (10 stars, last pushed 12d ago), licensed MIT. It adds 55 tokens to every session and 860 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.

js-config next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
js-configfubits1/svelte-skills	Skill	10	12d ago	MIT	A	55	Claude Code
imagegenopenai/codex	Skill	133k	yesterday	Apache-2.0	A	113	Codex
playwright-climicrosoft/playwright	Skill	99k	yesterday	Apache-2.0	A	19	Claude Code
local-ai-agentsmicrosoft/ai-agents-for-beginners	Skill	79k	4d ago	MIT	A	200	Claude Code, Codex
systematic-debuggingobra/superpowers	Skill	313k	3d ago	MIT	A	21	Claude Code
next-cache-components-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	95	Claude Code
next-partial-prefetching-adoptionvercel/next.js	Skill	143k	yesterday	MIT	A	103	Claude Code