aubade/src/core/index.js

filesystem-based content processor

import { matter } from '../artisan/index.js';
import { uhi } from '../utils.js';
export function parse(source) {
    const match = /---\r?\n([\s\S]+?)\r?\n---/.exec(source);
    if (!match)
        return { body: source };
    const crude = source.slice(match.index + match[0].length);
    const memory = matter(match[1].trim());
    const stuffed = inject(crude, memory);
    return {
        // @TODO: return AST (after implementing `markdown()`)
        body: stuffed.trim(),
        frontmatter: Object.assign(memory, {
            /** estimated reading time */
            get estimate() {
                const paragraphs = stuffed.split('\n').filter((p) => !!p && !/^[!*]/.test(p));
                const words = paragraphs.reduce((total, line) => {
                    if (/^[\t\s]*<.+>/.test(line.trim()))
                        return total + 1;
                    const accumulated = line.split(' ').filter((w) => !!w && /\w|\d/.test(w) && w.length > 1);
                    return total + accumulated.length;
                }, 0);
                const images = stuffed.match(/!\[.+\]\(.+\)/g);
                const total = words + (images || []).length * 12;
                return Math.round(total / 240) || 1;
            },
            /** table of contents */
            get table() {
                const table = [];
                for (const line of stuffed.replace(/<!--[\s\S]+?-->/g, '').split('\n')) {
                    const match = line.trim().match(/^(#{2,4}) (.+)/);
                    if (!match)
                        continue;
                    const [, hashes, title] = match;
                    const [delimited] = title.match(/\$\(.*?\)/) || [''];
                    table.push({
                        id: uhi(delimited.slice(2, -1) || title),
                        title: title.replace(delimited, delimited.slice(2, -1)),
                        level: hashes.length,
                    });
                }
                let parents = ['', ''];
                for (let i = 0; i < table.length; i++) {
                    const { id, level } = table[i];
                    if (level === 2)
                        parents = [id];
                    if (level === 3)
                        parents = [parents[0], id];
                    if (level === 4)
                        parents[2] = id;
                    table[i].id = parents.filter((p) => p).join('-');
                }
                return table;
            },
        }),
    };
}
function inject(source, metadata) {
    const plane = compress(metadata);
    return source.replace(/!{(.+)}/g, (s, c) => (c && plane[c]) || s);
}
function compress(metadata, parent = '') {
    const memo = {};
    const prefix = parent ? `${parent}:` : '';
    for (const [k, v] of Object.entries(metadata)) {
        if (typeof v !== 'object')
            memo[prefix + k] = v;
        else
            Object.assign(memo, compress(v, k));
    }
    return memo;
}