relatinator 3.3 · MIT
relatinator scores your documents against each other with BM25 or TF-IDF. It runs in Node.js, the browser, and Cloudflare Workers, and its only dependency is a stemmer. astro-relatinator hooks it into Astro content collections, so a related posts list is one getRelated call.
pnpm add relatinatorpnpm add astro-relatinatorrelated.tsBUILD TIMEimport { createModel } from "relatinator";
const model = createModel(posts);
model.findRelatedScored("science-books-space", { limit: 3 });cosmicspaceuniversuniverslatestphysicspacephysicrodriguezfindRelatedScored gives you the scores. explainRelated shows which words earned them, so you can check a strange match instead of guessing.
explain.tsmodel.explainRelated("science-books-space", "science-books-autumn");univers · 6.67latest · 3.81physic · 3.73dark · 2.83us · 2.35getRelated("posts", entry, { limit: 3 }) reads the collection when the page renders. It works with static output and with on-demand rendering.
const related = await getRelated("posts", entry,
{ limit: 3 });
return related;classify(topics, text) matches text against topic descriptions you write. You don't train anything or ship a model file, and the text never leaves your process.
const topics = [{ tag: "space", description }];
const best = classify(topics, text);Lowercases the text, removes elisions, splits on anything that isn't a letter or digit, drops stopwords, and stems what's left with Porter2.
Indexes the documents once and weights each term with BM25 or TF-IDF.
Adds up the weights of the query terms that a document contains.
Drops the query document, excluded documents, and anything that scored zero. Sorts the rest by score, keeps input order for ties, and returns as many ids as you asked for with limit.
| Target | relatinator | astro-relatinator |
|---|---|---|
| Node.js | 22.12 or later | 22.12 or later |
| Browsers | Yes | No, it runs at build time or on the server |
| Cloudflare | Workers | The Cloudflare adapter, with prerendering in workerd |
| Astro | Not needed | 6 and 7 |
| Astro output | Not needed | Static output and on-demand rendering |
| EmDash | Not needed | 1.x (1.0 or later), as an optional peer dependency |
| Module format | ES modules only, with type files | ES modules only, with type files |