MCPInstall

compat-review

by tossCode Quality & Workflow

Verify compat PR claims by running lodash vs es-toolkit/compat at runtime

Installs
217
Last 24h
—
Trending rank
—
Security
Not audited

Install

Works with every agent the skills CLI supports.

npx skills add https://github.com/toss/es-toolkit --skill compat-review
  1. 01

    Install

    Run the command in your project. The CLI asks which agents to install for.

  2. 02

    Describe the task

    Ask your agent for something this skill covers. It loads compat-review automatically when relevant.

  3. 03

    Review the result

    The agent follows the SKILL.md steps, scripts and references bundled with the skill.

SKILL.md

The instructions your agent reads when the skill is triggered.

Compat Layer Review

Verify that a compat PR actually fixes a real lodash inconsistency.

Input

$ARGUMENTS — PR number (e.g. 1234) or function name (e.g. chunk)

Workflow

1. Identify target function and PR claims

PR number:

gh pr view {number} --repo toss/es-toolkit --json title,body,files

From the PR description and diff, extract:

  • Which compat function is being fixed
  • What inconsistency the contributor claims (expected vs actual behavior)
  • Any test examples the contributor provides

Function name: Read the function source and its spec to understand current behavior.

2. Build comparison test

Create a temporary vitest spec at src/compat/{category}/_compat-review-{fn}.spec.ts.

import { describe, expect, it } from 'vitest';
import { fn as compatFn } from 'es-toolkit/compat';
import { fn as lodashFn } from 'lodash';

Include two groups of test cases:

A. Contributor's claimed examples — Extract directly from the PR description or test diff. These are the cases the PR claims to fix.

B. ~10 additional edge cases you generate — Based on the function's signature and lodash's known behavior patterns:

  • Empty inputs: [], {}, '', 0
  • Nullish: null, undefined
  • Negative/zero/float numbers: -1, 0, 1.5, NaN, Infinity
  • Type coercion: string numbers ('3'), boolean, mixed types
  • Boundary: single-element arrays, very long strings, deeply nested objects
  • Pick cases that are relevant to the specific function

Each test:

it('description', () => {
  let lodashResult, compatResult;
  let lodashErr: any, compatErr: any;
  try {
    lodashResult = lodashFn(args);
  } catch (e) {
    lodashErr = e;
  }
  try {
    compatResult = compatFn(args);
  } catch (e) {
    compatErr = e;
  }

  if (lodashErr && compatErr) return; // both throw = consistent
  if (lodashErr || compatErr) {
    throw new Error(`Behavior mismatch: ${lodashErr ? 'lodash throws' : 'compat throws'}`);
  }
  expect(compatResult).toEqual(lodashResult);
});

3. Run comparison BEFORE the PR change

yarn vitest run src/compat/{category}/_compat-review-{fn}.spec.ts

Record which tests fail — these are real inconsistencies that exist on main.

4. Apply PR changes and re-run

gh pr diff {number} --repo toss/es-toolkit | git apply

Run the same test again. Confirm that:

  • The contributor's claimed examples now pass
  • The additional edge cases still pass (no regressions)

Revert after testing:

git checkout -- .

5. Clean up

Delete _compat-review-*.spec.ts.

6. Report

## {fn} — Compat Review

### PR Claim
{What the contributor says they're fixing}

### Verification (BEFORE fix)
| # | Input | lodash | compat | Match? | Source |
|---|-------|--------|--------|--------|--------|
| 1 | ...   | ...    | ...    | MISMATCH | PR example |
| 2 | ...   | ...    | ...    | MATCH    | Edge case |

### Verification (AFTER fix)
| # | Input | lodash | compat | Match? | Source |
|---|-------|--------|--------|--------|--------|

### Verdict
- [ ] PR claim is valid (inconsistency confirmed on main)
- [ ] Fix resolves the claimed inconsistency
- [ ] No regressions in edge cases
- [ ] Existing tests still pass

FAQ

What does the compat-review skill do?

Verify compat PR claims by running lodash vs es-toolkit/compat at runtime

How do I install compat-review?

Run npx skills add https://github.com/toss/es-toolkit --skill compat-review in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/compat-review/ (personal) or .claude/skills/compat-review/ (project).

Which AI agents can use compat-review?

Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.

Is compat-review safe to install?

No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.

Who maintains compat-review?

It is published by toss in toss/es-toolkit. It has 217 recorded installs.

More from toss/es-toolkit

View all →

recommend

toss/es-toolkit

Analyze code or requirements and recommend the best es-toolkit functions. Use when the user asks which es-toolkit function to use, needs help finding a utility, or wants alternatives to manual implementations.

703 installs

guide

toss/es-toolkit

es-toolkit usage guide covering installation, import patterns, and setup for Node.js, Bun, Deno, and browsers. Use when the user asks how to install, import, or set up es-toolkit in their project.

Backend & APIs520 installs

migrate

toss/es-toolkit

Guide migrating lodash code to es-toolkit. Use when the user wants to migrate from lodash, replace lodash imports, reduce bundle size by switching to es-toolkit, or understand the difference between es-toolkit and es-toolkit/compat.

315 installs

pr-review

toss/es-toolkit

Open the skill to read its SKILL.md instructions.

Code Quality & Workflow189 installs

issue-review

toss/es-toolkit

Open the skill to read its SKILL.md instructions.

Code Quality & Workflow188 installs

release

toss/es-toolkit

Create a new es-toolkit release (version bump, changelog, tag)

188 installs

Popular code quality & workflow skills

View category →

grill-me

mattpocock/skills

A relentless interview to sharpen a plan or design.

Code Quality & Workflow1.4M installs

improve-codebase-architecture

mattpocock/skills

Scan a codebase for deepening opportunities, present them as a visual HTML report, then grill through whichever one you pick.

Code Quality & Workflow1.2M installs

handoff

mattpocock/skills

Compact the current conversation into a handoff document for another agent to pick up.

Code Quality & Workflow1.1M installs

domain-modeling

mattpocock/skills

Build and sharpen a project's domain model. Use when discussing codebase terminology, writing or editing a GLOSSARY.md, or recording or editing an ADR.

Code Quality & Workflow890.6K installs

codebase-design

mattpocock/skills

Shared vocabulary for designing deep modules. Use when the user wants to design or improve a module's interface, find deepening opportunities, decide where a seam goes, make code more testable or AI-navigable, or when another skill needs the deep-module vocabulary.

Code Quality & Workflow863.8K installs

diagnosing-bugs

mattpocock/skills

Diagnosis loop for hard bugs and performance regressions. Use when the user says "diagnose"/"debug this", or reports something broken/throwing/failing/slow.

Code Quality & Workflow848.4K installs