yoastjs

Simple SEO & Readability Analysis for JavaScript — powered by Yoast SEO

yoastjs is a lightweight wrapper built on top of Yoast SEO that makes SEO and readability analysis easy to use in Node.js, browsers, ESM, CJS, and TypeScript — without dealing with Yoast’s internal APIs or module compatibility issues.

❗ The Problem with Yoast SEO in Modern JS

The official Yoast SEO (yoastseo) package is CommonJS-only.

This causes multiple issues in modern JavaScript projects:

• ❌ Does not work cleanly with ES Modules
• ❌ Difficult to import in TypeScript (NodeNext / ESM)
• ❌ Breaks in browser environments without heavy polyfills
• ❌ No default types for seamless TS usage

Using Yoast directly often results in:

• require is not defined
• Cannot use import statement outside a module
• Broken builds in Vite / Next.js / ESBuild

✅ How yoastjs Solves This

yoastjs abstracts all Yoast SEO internals and provides:

• ✅ Dual builds: ESM + CommonJS
• ✅ Browser-compatible bundle
• ✅ Node.js support
• ✅ First-class TypeScript types
• ✅ No need to import Yoast directly
• ✅ Automatic environment resolution via exports

You write modern import syntax, and the correct build is picked automatically.

✨ Features

• Built on top of Yoast SEO
• Simple one-function API
• SEO + Readability analysis
• Works in Node & Browser
• Supports ESM, CJS, TypeScript
• Fully typed results
• Tree-shakable
• Zero configuration

📦 Installation

npm install yoastjs

or

pnpm add yoastjs

or

yarn add yoastjs

🚀 Quick Start

ESM / TypeScript

import { analyzeContent } from "yoastjs";

const result = analyzeContent({
  title: "What is SEO?",
  slug: "what-is-seo",
  description: "Learn what SEO is and why it matters",
  content: "SEO stands for Search Engine Optimization...",
  keyphrase: "SEO",
});

console.dir(result);

CommonJS (Node.js)

const { analyzeContent } = require("yoastjs");

const result = analyzeContent({
  content: "SEO stands for Search Engine Optimization...",
  keyphrase: "SEO",
});

console.dir(result);

Browser (Vite / Webpack / ESBuild)

import { analyzeContent } from "yoastjs";

const analysis = analyzeContent({
  content: document.querySelector("#editor").value,
  keyphrase: "javascript seo",
});

console.dir(analysis);

🧠 API

analyzeContent(input)

Runs SEO and readability analysis on the provided content.

interface AnalyzeInput {
  title?: string;
  slug?: string;
  description?: string;
  content?: string;
  keyphrase?: string;
  locale?: string; // default: "en_US"
}

📊 Result Format

{
  seo: AnalyzerResult;
  readability: AnalyzerResult;
}

AnalyzerResult

interface AnalyzerResult {
  score: number;
  rating: "good" | "ok" | "bad" | "feedback" | "error";
  results: AnalysisItem[];
}

🌍 Locale Support

English (en_US) by default.

🛠 Build & Compatibility

This package ships environment-specific builds:

| Environment | Supported | | ----------- | --------- | | Node.js | ✅ | | Browser | ✅ | | ESM | ✅ | | CommonJS | ✅ | | TypeScript | ✅ |

Thanks to conditional exports, bundlers automatically select the correct version.

📁 Package Output

dist/
├── browser/
│   ├── index.js
│   └── index.d.ts
├── node/
│   ├── index.js
│   ├── index.cjs
│   └── index.d.ts

🤝 Why yoastjs?

Because content analysis should be simple, not blocked by legacy module formats.

yoastjs lets you use Yoast’s powerful engine in modern JavaScript without friction.

📝 License

MIT