og-images-generator/dist/collect.js

Generate OG images from a static folder and / or a middleware. Extract metadata from HTML pages. No headless browser involved. Comes as a CLI, API or plugins.

import path from 'node:path';
import fs from 'node:fs';
import fastGlob from 'fast-glob';
import { parse } from 'parse5';
import c from 'picocolors';
export function extractMetadataFromHtml(fileContent) {
    const ast = parse(fileContent);
    const document_ = ast.childNodes.find((node) => node.nodeName === 'html');
    if (document_ === undefined)
        throw new Error('Invalid base HTML document.');
    if ('childNodes' in document_ === false)
        throw new Error('Invalid base HTML document.');
    const head = document_.childNodes.find((node) => node.nodeName === 'head');
    if (head === undefined)
        throw new Error('Invalid HTML head element.');
    if ('childNodes' in head === false)
        throw new Error('Invalid HTML head element.');
    const body = document_.childNodes.find((node) => node.nodeName === 'body');
    if (body === undefined)
        throw new Error('Invalid HTML body element.');
    if ('childNodes' in body === false)
        throw new Error('Invalid HTML body element.');
    const metaTagsNode = head.childNodes.filter((node) => ['meta'].includes(node.nodeName));
    const jsonLds = [];
    for (const node of [...head.childNodes, ...body.childNodes]) {
        if (['script'].includes(node.nodeName) &&
            'attrs' in node &&
            node.attrs.find((attribute) => attribute.name === 'type')?.value ===
                'application/ld+json') {
            const content = node.childNodes.at(0);
            if (content && 'value' in content)
                jsonLds.push(JSON.parse(content.value));
        }
    }
    const metaTags = {};
    for (const node of metaTagsNode) {
        if ('attrs' in node === false)
            continue;
        node.attrs.map((attribute) => {
            if (attribute.name === 'property' || attribute.name === 'name') {
                const metaName = attribute.value;
                const metaValue = node.attrs.find((attr) => attr.name === 'content')?.value;
                if (metaValue)
                    metaTags[metaName] = metaValue;
            }
        });
    }
    return { tags: metaTags, jsonLds };
}
export async function collectHtmlPages(options) {
    // eslint-disable-next-line no-console
    console.log(c.bold(c.yellow('Collecting HTML pages…')));
    const files = await fastGlob([path.join(options.base, '**/*.html'), ...options.additionalPatterns], options.globber);
    const pages = [];
    await Promise.all(files.map(async (filePath) => {
        const fileContent = await fs.promises.readFile(filePath, 'utf8');
        const pageMetas = extractMetadataFromHtml(fileContent);
        pages.push({
            path: path.relative(options.base, filePath),
            meta: pageMetas,
        });
    }));
    await fs.promises
        .mkdir(path.join(options.out), { recursive: true })
        .catch(() => null);
    await fs.promises.writeFile(path.join(options.json), JSON.stringify(pages, null, 2));
    return pages.sort((p, n) => (p.path < n.path ? -1 : 1));
}