react-is 19.x

Use react-is 19 to identify React element brands and validate component types. Covers the React 19 export surface, the removal of React 18 async/concurrent aliases, and standalone checks that run without JSX, React, a DOM, or a test runner.

For

react-is@19.2.8

Verified

2026-09-08, 2 examples executed

Package

@modootoday/pmcp-react-is@19.0.0

What it covers

• React 19 exports
• Validate component types
• Check arbitrary values without React or JSX
• React-created values
• Portals
• React 18 compatibility trap
• TypeScript
• Not covered

One example from this skill

This is the skill's own text, not a summary of it. It runs: that is what verifying means here.

import * as assert from "node:assert/strict";
import * as ReactIs from "react-is";

function Component() {
  return null;
}

assert.equal(ReactIs.isValidElementType("div"), true);
assert.equal(ReactIs.isValidElementType(Component), true);
assert.equal(ReactIs.isValidElementType(null), false);
assert.equal(ReactIs.isValidElementType({}), false);

What it did in the sandbox

Verifying this skill meant installing the package and running code against it with no route out. Nothing was observed. The full ledger lists every package examined, including the ones that never became a skill.

Nothing observed is not a finding of safety. It means one run, under one policy, produced nothing to report.

Getting it

With a subscription:

npx -y @modootoday/pmcp login
npx -y @modootoday/pmcp install @modootoday/pmcp-react-is

It installs as a dev dependency of your project, and the MCP server finds it there like any other skill.