@sdoc/markdown-loader/lib/markdown/snippet.js

san markdown loader

// Modified from https://github.com/vuejs/vuepress/blob/fda5476aa1/packages/%40vuepress/markdown/lib/snippet.js
const fs = require('fs');
const path = require('path');

module.exports = function snippet(md, options = {}) {
    const fence = md.renderer.rules.fence;
    const root = options.root || process.cwd();

    md.renderer.rules.fence = (...args) => {
        const [tokens, idx, , {loader}] = args;
        const token = tokens[idx];
        const {src} = token;
        if (src) {
            if (loader) {
                loader.addDependency(src);
            }
            if (fs.existsSync(src)) {
                token.content = fs.readFileSync(src, 'utf8');
            } else {
                token.content = 'Not found: ' + src;
                token.info = '';
            }
        }
        return fence(...args);
    };

    function parser(state, startLine, endLine, silent) {
        const CH = '<'.charCodeAt(0);
        const pos = state.bMarks[startLine] + state.tShift[startLine];
        const max = state.eMarks[startLine];

        // if it's indented more than 3 spaces, it should be a code block
        if (state.sCount[startLine] - state.blkIndent >= 4) {
            return false;
        }

        for (let i = 0; i < 3; ++i) {
            const ch = state.src.charCodeAt(pos + i);
            if (ch !== CH || pos + i >= max) {
                return false;
            }
        }

        if (silent) {
            return true;
        }

        const start = pos + 3;
        const end = state.skipSpacesBack(max, pos);
        const rawPath = state.src
            .slice(start, end)
            .trim()
            .replace(/^@/, root);
        const filename = rawPath
            .split(/{/)
            .shift()
            .trim();
        const meta = rawPath.replace(filename, '');

        state.line = startLine + 1;

        const token = state.push('fence', 'code', 0);
        token.info = filename.split('.').pop() + meta;
        token.src = path.resolve(filename);
        token.markup = '```';
        token.map = [startLine, startLine + 1];

        return true;
    }

    md.block.ruler.before('fence', 'snippet', parser);
};