documentation/lib/output/markdown_ast.js

a documentation generator

'use strict';

const u = require('unist-builder');
const remark = require('remark');
const mergeConfig = require('../merge_config');
const toc = require('remark-toc');
const links = require('remark-reference-links');
const hljs = require('highlight.js');
const GithubSlugger = require('github-slugger');
const LinkerStack = require('./util/linker_stack');
const rerouteLinks = require('./util/reroute_links');
const _formatType = require('./util/format_type');

const DEFAULT_LANGUAGE = 'javascript';

/**
 * Given a hierarchy-nested set of comments, generate an remark-compatible
 * Abstract Syntax Tree usable for generating Markdown output
 *
 * @param  comments nested comment
 * @param {Object} args currently none accepted
 * @param {boolean} [args.markdownToc=true] whether to include a table of contents
 * in markdown output.
 * @param {Object} [args.hljs={}] config to be passed to highlightjs for code highlighting:
 * consult hljs.configure for the full list.
 * @returns {Promise<Object>} returns an eventual Markdown value
 */
function markdownAST(comments, args) {
  return mergeConfig(args).then(config => buildMarkdownAST(comments, config));
}

function buildMarkdownAST(comments, config) {
  // Configure code highlighting
  const hljsOptions = config.hljs || {};
  hljs.configure(hljsOptions);

  const linkerStack = new LinkerStack(config).namespaceResolver(comments, namespace => {
    const slugger = new GithubSlugger();
    return '#' + slugger.slug(namespace);
  });

  const formatType = _formatType.bind(undefined, linkerStack.link);

  const generatorComment = [u('html', '<!-- Generated by documentation.js. Update this documentation by updating the source code. -->')];

  const tableOfContentsHeading = [u('heading', { depth: 3 }, [u('text', 'Table of Contents')])];

  /**
   * Generate an AST chunk for a comment at a given depth: this is
   * split from the main function to handle hierarchially nested comments
   *
   * @param {number} depth nesting of the comment, starting at 1
   * @param {Object} comment a single comment
   * @returns {Object} remark-compatible AST
   */
  function generate(depth, comment) {
    function typeSection(comment) {
      return comment.type && u('paragraph', [u('text', 'Type: ')].concat(formatType(comment.type)));
    }

    function paramList(params) {
      if (params.length === 0) return [];
      return u('list', { ordered: false }, params.map(param => u('listItem', [u('paragraph', [u('inlineCode', param.name), u('text', ' '), !!param.type && u('strong', formatType(param.type)), u('text', ' ')].concat(param.description ? param.description.children : []).concat([!!param.default && u('paragraph', [u('text', ' (optional, default '), u('inlineCode', param.default), u('text', ')')])]).filter(Boolean))].concat(param.properties && paramList(param.properties)).filter(Boolean))));
    }

    function paramSection(comment) {
      return comment.params.length > 0 && [u('strong', [u('text', 'Parameters')]), paramList(comment.params)];
    }

    function propertySection(comment) {
      return comment.properties.length > 0 && [u('strong', [u('text', 'Properties')]), propertyList(comment.properties)];
    }

    function propertyList(properties) {
      return u('list', { ordered: false }, properties.map(property => u('listItem', [u('paragraph', [u('inlineCode', property.name), u('text', ' '), u('strong', formatType(property.type)), u('text', ' ')].concat(property.description ? property.description.children : []).filter(Boolean)), property.properties && propertyList(property.properties)].filter(Boolean))));
    }

    function examplesSection(comment) {
      return comment.examples.length > 0 && [u('strong', [u('text', 'Examples')])].concat(comment.examples.reduce(function (memo, example) {
        const language = hljsOptions.highlightAuto ? hljs.highlightAuto(example.description).language : DEFAULT_LANGUAGE;
        return memo.concat(example.caption ? [u('paragraph', [u('emphasis', example.caption)])] : []).concat([u('code', { lang: language }, example.description)]);
      }, []));
    }

    function returnsSection(comment) {
      return comment.returns.length > 0 && comment.returns.map(returns => u('paragraph', [u('text', 'Returns '), u('strong', formatType(returns.type)), u('text', ' ')].concat(returns.description ? returns.description.children : [])));
    }

    function throwsSection(comment) {
      return comment.throws.length > 0 && u('list', { ordered: false }, comment.throws.map(returns => u('listItem', [u('paragraph', [u('text', 'Throws '), u('strong', formatType(returns.type)), u('text', ' ')].concat(returns.description ? returns.description.children : []))])));
    }

    function augmentsLink(comment) {
      return comment.augments.length > 0 && u('paragraph', [u('strong', [u('text', 'Extends '), u('text', comment.augments.map(tag => tag.name).join(', '))])]);
    }

    function seeLink(comment) {
      return comment.sees.length > 0 && u('list', { ordered: false }, comment.sees.map(see => u('listItem', [u('strong', [u('text', 'See: ')].concat(see.children))])));
    }

    function githubLink(comment) {
      return comment.context && comment.context.github && u('paragraph', [u('link', {
        title: 'Source code on GitHub',
        url: comment.context.github.url
      }, [u('text', comment.context.github.path + ':' + comment.context.loc.start.line + '-' + comment.context.loc.end.line)])]);
    }

    function metaSection(comment) {
      const meta = ['version', 'since', 'copyright', 'author', 'license', 'deprecated'].filter(tag => comment[tag]);
      return !!meta.length && [u('strong', [u('text', 'Meta')])].concat(u('list', { ordered: false }, meta.map(tag => {
        let metaContent;
        if (tag === 'copyright' || tag === 'deprecated') {
          metaContent = comment[tag];
        } else {
          metaContent = u('text', comment[tag]);
        }
        return u('listItem', [u('paragraph', [u('strong', [u('text', tag)]), u('text', ': '), metaContent])]);
      })));
    }

    if (comment.kind === 'note') {
      return [u('heading', { depth }, [u('text', comment.name || '')])].concat(comment.description).concat(!!comment.members.static.length && comment.members.static.reduce((memo, child) => memo.concat(generate(depth + 1, child)), [])).filter(Boolean);
    }

    return [u('heading', { depth }, [u('text', comment.name || '')])].concat(githubLink(comment)).concat(augmentsLink(comment)).concat(seeLink(comment)).concat(comment.description ? comment.description.children : []).concat(typeSection(comment)).concat(paramSection(comment)).concat(propertySection(comment)).concat(examplesSection(comment)).concat(throwsSection(comment)).concat(returnsSection(comment)).concat(metaSection(comment)).concat(!!comment.members.global.length && comment.members.global.reduce((memo, child) => memo.concat(generate(depth + 1, child)), [])).concat(!!comment.members.instance.length && comment.members.instance.reduce((memo, child) => memo.concat(generate(depth + 1, child)), [])).concat(!!comment.members.static.length && comment.members.static.reduce((memo, child) => memo.concat(generate(depth + 1, child)), [])).concat(!!comment.members.inner.length && comment.members.inner.reduce((memo, child) => memo.concat(generate(depth + 1, child)), [])).filter(Boolean);
  }

  let root = rerouteLinks(linkerStack.link, u('root', generatorComment.concat(config.markdownToc ? tableOfContentsHeading : []).concat(comments.reduce((memo, comment) => memo.concat(generate(2, comment)), []))));

  const pluginRemark = remark();
  if (config.markdownToc) pluginRemark.use(toc, { tight: true });
  if (config.noReferenceLinks !== true) pluginRemark.use(links);
  root = pluginRemark.run(root);

  return Promise.resolve(root);
}

module.exports = markdownAST;