#Measurement catalog

Rules return verdicts. Collectors return numbers. This is the catalog of the numbers.

Every metric id is category/name, using the same categories as the rules, so only and skip filter both at once. Nothing here touches the score.

import { allCollectors, selectRules } from "safi-studio-scanner";

const report = await audit("https://example.com");
const titleLength = report.pages[0].metrics.find((m) => m.id === "core-seo/title-chars");

#Status values

A metric with no status is a plain count with no correct answer, like the number of hidden elements.

#Core SEO

A tag's state is present, missing or not set. The difference matters: missing means a card will not render properly without it, not set means the card works and would be sharper with it. Only og:title, og:description and og:image can be missing.

#Content

The outline is the page's table of contents as the parser sees it. A heading's section is everything between it and the next heading at any level, and the third column names what that section carries: IMG: 1, UL: 1 says the section has a picture and a list. An empty heading is listed as (empty) rather than vanishing into a blank row. Capped at 40 rows.

Hidden elements are counted from inline styles only. There is no CSS cascade in a static parse, so a class that hides an element in a stylesheet is invisible here.

#Crawlability

A canonical that points elsewhere is warn, not bad. It is the correct thing to do on a paginated or filtered page, and only you know which this is.

#Links

The duplicate table is the one to read. It is sorted by count, and it answers a question no per-link list can: this page links /pricing three times, once as "Pricing", once as "pricing page", once as "the plans". That is either a deliberate spread of anchor text or an accident, and seeing them on one row is what tells you which.

All three tables are omitted when the page has no links of that kind.

#Images

alt="" and a missing alt are counted separately. An empty alt is a decision, saying the image is decorative and screen readers should skip it. A missing attribute is an omission. The note on images/with-alt splits the two.

#Social media

Only twitter:card counts as required. Twitter falls back to Open Graph for the title, description and image, so an empty table next to a full Open Graph one is a working card, not a broken one.

#Internationalization

#Performance

#Reading them

// One value across the whole crawl.
for (const page of report.pages) {
  const size = page.metrics.find((m) => m.id === "performance/html-size");
  if (size?.status !== "ok") console.log(page.url, size?.value, size?.unit);
}

// Every table on the start page.
const tables = report.pages[0].metrics.filter((m) => m.kind === "table");

To add your own, see writing a collector.