toc.ts

import { slugifyGH } from "@thi.ng/strings";
import {
    PATTERN_NO_TOC,
    PATTERN_TOC,
    RE_HEADING,
    RE_IS_HEADING
} from "./api";
import { link } from "./partials/link";

export const injectTOC = (readme: string) => {
    const toc = readme
        .split("\n")
        .filter(
            (line) =>
                RE_IS_HEADING.test(line) && line.indexOf(PATTERN_NO_TOC) === -1
        )
        .map((hd) => {
            const [_, level, title] = RE_HEADING.exec(hd)!;
            const indent = "      ".substr(0, (level.length - 2) * 2);
            const href = "#" + slugifyGH(title);
            return `${indent}- ${link(title, href)}`;
        })
        .join("\n");
    return readme.replace(PATTERN_TOC, toc);
};