Stats

stats(presentation, options?) and opf stats <file|-> report neutral facts about a deck: what is in it and how much. Counts and lists only. There are no severities, no judgments and no thresholds, so nothing here says a deck is too long, too dense or missing something; opf validate says what is wrong, and a reviewer decides what is good.

import { stats } from '@openpresentation/opf';

const facts = stats(deck);
facts.slides.total;                 // 12
facts.words.content;                // 842 words on the slides
facts.notes.withoutNotes;           // [{ index: 3, id: 'pricing' }, ...]
facts.images.content.missingAlt;    // 2
facts.speakingTime;                 // { basis: 'estimate', wordsPerMinute: 130, notesWords: 410, minutes: 3.2, declaredMinutes: 20 }
stats(deck, { perSlide: true }).perSlide;   // one row per slide

opf stats deck.opf.json                      # JSON: the report { command, ok, input, ..., stats } (CLI 0.18; the facts alone before)
opf stats deck.opf.json --format text        # one readable block per topic
opf stats - --per-slide < deck.opf.json      # adds a row per slide

What it does and does not do#

• Structural only. It walks the JSON. It does not compose slides, build layouts, measure text or need fonts, and it does not validate: a deck that fails opf validate still has facts, and an unknown id is reported as written. It reads what is there and never throws on a malformed deck (it throws only for an argument that is not an object).
• Cheap. Measured on the 126 bundled example decks, warm, with the per-slide breakdown: 18 ms for all of them (0.14 ms mean), against 46 ms for validate(deck, { only: ['format'] }), 290 ms for only: ['format', 'references'] and 1.1 s for a full validate over the same decks (one machine; the ratios hold). Template variables are read with listVariables; nothing else loads a catalog except the theme and font-scheme records that name a size and families.
• Deterministic. The same deck gives the same output with the same key order: objects are built in a fixed order, and every count map and id list is sorted (slide lists keep deck order). Nothing reads a clock, a locale or the runtime's Unicode word-break data.
• Pure. The input is not changed.

stats(presentation, { perSlide?, values?, wordsPerMinute? }): perSlide adds perSlide, values is a variables map to count as filled (as for resolveVariables), wordsPerMinute sets the speaking pace of the estimate (default 130). The root also exports the result types (PresentationStats, SlideStats, ...).

The report#

Definitions#

• Words. Letters and digits in a run, with an internal apostrophe, hyphen, comma or period joining parts (don't, well-known, 3.5, $4.2M is one word). Thai, Lao, Myanmar, Khmer, kana and Han text, which has no spaces between words, counts one unit per character: a fixed rule, so a count never depends on the runtime's Unicode data. Content words are the visible text on slides: title, subtitle, tag, text, items (and their descriptions), bullets, quote text, attribution and source, metric fields, timeline fields, table headers and cells (a number is one word), and captions. Code, chart data, header and footer text and reference texts are not counted. A dataset-backed table has no cells of its own. Variable tokens ({{name}}) are counted as written. Notes words are the words of notes.
• Speaking time is notesWords / wordsPerMinute. It is an estimate of reading the notes aloud at a steady pace, labelled as one in the report. The deck's own duration is reported next to it, not compared to it.
• Images. content counts image payloads (slide root, blocks, regions, placed or not). Alt text follows the asset: references to the registry. An alt text that is empty (alt: "") is decorative, the explicit choice opf validate accepts; no alt, or only whitespace, is missing. Logos, watermarks and image backgrounds are decorative or brand assets by nature and are counted separately, not as content images.
• Assets. A source starting asset: is a registry reference, data: is embedded, http(s): (and pkg:) is remote, anything else is a file (a relative path resolved against the OPF file, or a local path). embeddedBytes is the decoded size of data: URIs (exact for base64). A chart that takes its data from an external source counts that source as a use; a source on inline data or a dataset is provenance, never read, and is not a use.
• Fonts. Families come from the font schemes in effect (the deck's, and a slide's own scheme or theme), inline scheme records, and fontFamily on runs, resolved the way every engine resolves them. A scheme that names no code role does not add a code family.

What stats leaves out#

Everything in the schema that is presentation detail rather than a countable or present fact is left out; the deck itself has it: text run formatting (bold, colour, size), list numbering styles, chart styling (axis titles, legend, data labels, series mapping), table cell styles and spans, composition hints, design preferences such as alignment, contentBox, contentDirection, chartPrimary, imageFit, listBullet, image treatments and placement, solid and gradient backgrounds, the individual Language, Tone and Audience record fields, and the contents of extensions. Findings (alt text that is missing, a missing title, text that overflows) belong to opf validate, which reports them with severities; stats only counts the underlying things.