Presets

A preset is a config that your config merges in first. Use a preset to share one set of rules across sites, or to switch rules for one environment, such as a staging deploy.

Use a preset

Add presets to the presets field of seolint.config.ts:

import * as config from "seolint/config";
import * as presets from "seolint/presets";

export default config.define({
  host: "https://example.com",
  presets: [presets.strict],
  rules: { "og.*": false },
});

To use a different preset for each environment, choose it in the config:

import * as config from "seolint/config";
import * as presets from "seolint/presets";

let staging = process.env.DEPLOY_ENV === "staging";

export default config.define({
  host: staging ? "https://staging.example.com" : "https://example.com",
  presets: staging ? [presets.staging] : [presets.strict],
});

How presets merge

seolint merges each preset in order, then your config. A preset can have its own presets, which merge in first.

A rule pattern, such as "og.*", also replaces every earlier setting that it matches. So one pattern in your config undoes a preset for a group of rules:

export default config.define({
  presets: [presets.strict], // sets "og.title": "error", "og.image": "error", ...
  rules: { "og.*": "warn" }, // every og rule is a warning again
});

Inside one rules object, patterns apply first, then exact names. So { "og.*": false, "og.title": true } turns on only og.title.

Built-in presets

Import the built-in presets from seolint/presets:

• strict turns every rule that defaults to a warning into an error.
• essentials keeps only the rules that directly affect search results.
• staging allows noindex on staging and preview deploys.

Write your own

A preset is a config. Make one with define(), the same as seolint.config.ts:

// seolint.base.ts
import * as config from "seolint/config";
import * as presets from "seolint/presets";

export default config.define({
  presets: [presets.strict],
  ignore: ["drafts/**"],
  rules: {
    "title.content.length": { max: 70 },
    "twitter.*": false,
  },
});

// seolint.config.ts
import * as config from "seolint/config";
import base from "./seolint.base.ts";

export default config.define({
  host: "https://example.com",
  presets: [base],
});

A preset can set any config field. Leave host and inputs to each site, unless all sites share them.

Share a preset

To use one preset across many sites, publish it as a package. Export the config, and add seolint as a peer dependency:

// @acme/seolint-preset
import * as config from "seolint/config";

export default config.define({
  rules: { "og.*": "error", "link.external.limit": { max: 5 } },
});

{
  "name": "@acme/seolint-preset",
  "type": "module",
  "exports": "./index.js",
  "peerDependencies": {
    "seolint": "*"
  }
}

Publish JavaScript, or TypeScript types with it. Node does not strip types from files in node_modules.

Add plugins

A preset can include plugins. Configs that use the preset run them, and can set their rules:

// @acme/seolint-preset
import * as config from "seolint/config";

const brand = config.plugin({
  name: "brand",
  rules: { "brand.title": { name: "" } },
  run(context, document) {
    // ...
  },
});

export default config.define({
  plugins: [brand],
  rules: { "brand.title": { name: "Acme" } },
});

// seolint.config.ts
import * as config from "seolint/config";
import acme from "@acme/seolint-preset";

export default config.define({
  presets: [acme],
  rules: { "brand.title": { name: "Acme Docs" } },
});

define() remembers the plugins of a config, so the config that uses it type-checks their rules too. Here, "brand.title": { name: 1 } is a type error.

A plugin replaces an earlier plugin with the same name, so two presets can include the same plugin. Two plugins with different names cannot declare the same rule.