shelving/extract/IndexFileExtractor.js

Toolkit for using data in JavaScript.

import { mergeElements, walkElements } from "../util/element.js";
import { anyMatch } from "../util/regexp.js";
import { ThroughExtractor } from "./ThroughExtractor.js";
/**
 * Default index file patterns.
 * - Matched case-insensitively (all entries stored lowercase).
 * - The first child of a directory that matches any pattern is absorbed.
 */
const DEFAULT_INDEX = [/^readme\.txt$/i, /^readme\.md$/i, /^index\.md$/i, /^index\.ts$/i, /^index\.tsx$/i];
/**
 * Through extractor that walks a `DirectoryElement` tree and absorbs each directory's index file into the directory itself.
 * - For each directory: finds the first child whose `key` matches any `index` pattern.
 * - The matched child's `title`, `description`, `content`, and `children` are folded into the parent directory.
 * - The matched child is removed from the parent's children list.
 * - Recurses into subdirectories before absorbing — the deepest level happens first.
 */
export class IndexFileExtractor extends ThroughExtractor {
    _index;
    constructor(source, { index = DEFAULT_INDEX } = {}) {
        super(source);
        this._index = index;
    }
    async extract(input) {
        const root = await this.source.extract(input);
        return _absorbIndex(root, this._index);
    }
}
/** Recursively absorb the index file in `dir` and all nested directories. */
function _absorbIndex(dir, index) {
    // Recurse first so nested directories absorb their own indexes before we look at this level.
    const recursed = Array.from(walkElements(dir.props.children)).map(child => child.type === "tree-directory" ? _absorbIndex(child, index) : child);
    // Find the index child by key.
    const indexChild = recursed.find(child => anyMatch(child.key, ...index));
    if (!indexChild)
        return { ...dir, props: { ...dir.props, children: recursed } };
    // Fold the index child into the directory, and drop it from children.
    const remaining = recursed.filter(child => child !== indexChild);
    return {
        ...dir,
        props: {
            ...dir.props,
            title: dir.props.title ?? indexChild.props.title,
            description: dir.props.description ?? indexChild.props.description,
            content: dir.props.content ?? indexChild.props.content,
            children: mergeElements(indexChild.props.children, remaining),
        },
    };
}