diff options
Diffstat (limited to 'app/assets/javascripts/lib/gfm')
4 files changed, 104 insertions, 3 deletions
diff --git a/app/assets/javascripts/lib/gfm/constants.js b/app/assets/javascripts/lib/gfm/constants.js new file mode 100644 index 00000000000..eaabeb2a767 --- /dev/null +++ b/app/assets/javascripts/lib/gfm/constants.js @@ -0,0 +1,10 @@ +export const TABLE_OF_CONTENTS_DOUBLE_BRACKET_OPEN_TOKEN = '[['; +export const TABLE_OF_CONTENTS_DOUBLE_BRACKET_MIDDLE_TOKEN = 'TOC'; +export const TABLE_OF_CONTENTS_DOUBLE_BRACKET_CLOSE_TOKEN = ']]'; +export const TABLE_OF_CONTENTS_SINGLE_BRACKET_TOKEN = '[TOC]'; + +export const MDAST_TEXT_NODE = 'text'; +export const MDAST_EMPHASIS_NODE = 'emphasis'; +export const MDAST_PARAGRAPH_NODE = 'paragraph'; + +export const GLFM_TABLE_OF_CONTENTS_NODE = 'tableOfContents'; diff --git a/app/assets/javascripts/lib/gfm/glfm_extensions/table_of_contents.js b/app/assets/javascripts/lib/gfm/glfm_extensions/table_of_contents.js new file mode 100644 index 00000000000..4d2484a657a --- /dev/null +++ b/app/assets/javascripts/lib/gfm/glfm_extensions/table_of_contents.js @@ -0,0 +1,85 @@ +import { first, last } from 'lodash'; +import { u } from 'unist-builder'; +import { visitParents, SKIP, CONTINUE } from 'unist-util-visit-parents'; +import { + TABLE_OF_CONTENTS_DOUBLE_BRACKET_CLOSE_TOKEN, + TABLE_OF_CONTENTS_DOUBLE_BRACKET_MIDDLE_TOKEN, + TABLE_OF_CONTENTS_DOUBLE_BRACKET_OPEN_TOKEN, + TABLE_OF_CONTENTS_SINGLE_BRACKET_TOKEN, + MDAST_TEXT_NODE, + MDAST_EMPHASIS_NODE, + MDAST_PARAGRAPH_NODE, + GLFM_TABLE_OF_CONTENTS_NODE, +} from '../constants'; + +const isTOCTextNode = ({ type, value }) => + type === MDAST_TEXT_NODE && value === TABLE_OF_CONTENTS_DOUBLE_BRACKET_MIDDLE_TOKEN; + +const isTOCEmphasisNode = ({ type, children }) => + type === MDAST_EMPHASIS_NODE && children.length === 1 && isTOCTextNode(first(children)); + +const isTOCDoubleSquareBracketOpenTokenTextNode = ({ type, value }) => + type === MDAST_TEXT_NODE && value.trim() === TABLE_OF_CONTENTS_DOUBLE_BRACKET_OPEN_TOKEN; + +const isTOCDoubleSquareBracketCloseTokenTextNode = ({ type, value }) => + type === MDAST_TEXT_NODE && value.trim() === TABLE_OF_CONTENTS_DOUBLE_BRACKET_CLOSE_TOKEN; + +/* + * Detects table of contents declaration with syntax [[_TOC_]] + */ +const isTableOfContentsDoubleSquareBracketSyntax = ({ children }) => { + if (children.length !== 3) { + return false; + } + + const [firstChild, middleChild, lastChild] = children; + + return ( + isTOCDoubleSquareBracketOpenTokenTextNode(firstChild) && + isTOCEmphasisNode(middleChild) && + isTOCDoubleSquareBracketCloseTokenTextNode(lastChild) + ); +}; + +/* + * Detects table of contents declaration with syntax [TOC] + */ +const isTableOfContentsSingleSquareBracketSyntax = ({ children }) => { + if (children.length !== 1) { + return false; + } + + const [firstChild] = children; + const { type, value } = firstChild; + + return type === MDAST_TEXT_NODE && value.trim() === TABLE_OF_CONTENTS_SINGLE_BRACKET_TOKEN; +}; + +const isTableOfContentsNode = (node) => + node.type === MDAST_PARAGRAPH_NODE && + (isTableOfContentsDoubleSquareBracketSyntax(node) || + isTableOfContentsSingleSquareBracketSyntax(node)); + +export default () => { + return (tree) => { + visitParents(tree, (node, ancestors) => { + const parent = last(ancestors); + + if (!parent) { + return CONTINUE; + } + + if (isTableOfContentsNode(node)) { + const index = parent.children.indexOf(node); + + parent.children[index] = u(GLFM_TABLE_OF_CONTENTS_NODE, { + position: node.position, + }); + } + + return SKIP; + }); + + return tree; + }; +}; diff --git a/app/assets/javascripts/lib/gfm/index.js b/app/assets/javascripts/lib/gfm/index.js index eaf653e9924..fad73f93c1a 100644 --- a/app/assets/javascripts/lib/gfm/index.js +++ b/app/assets/javascripts/lib/gfm/index.js @@ -6,6 +6,8 @@ import remarkFrontmatter from 'remark-frontmatter'; import remarkGfm from 'remark-gfm'; import remarkRehype, { all } from 'remark-rehype'; import rehypeRaw from 'rehype-raw'; +import glfmTableOfContents from './glfm_extensions/table_of_contents'; +import * as glfmMdastToHastHandlers from './mdast_to_hast_handlers/glfm_mdast_to_hast_handlers'; const skipFrontmatterHandler = (language) => (h, node) => h(node.position, 'frontmatter', { language }, [{ type: 'text', value: node.value }]); @@ -65,19 +67,22 @@ const skipRenderingHandlers = { all(h, node), ); }, + tableOfContents: (h, node) => h(node.position, 'tableOfContents'), toml: skipFrontmatterHandler('toml'), yaml: skipFrontmatterHandler('yaml'), json: skipFrontmatterHandler('json'), }; -const createParser = ({ skipRendering = [] }) => { +const createParser = ({ skipRendering }) => { return unified() .use(remarkParse) .use(remarkGfm) .use(remarkFrontmatter, ['yaml', 'toml', { type: 'json', marker: ';' }]) + .use(glfmTableOfContents) .use(remarkRehype, { allowDangerousHtml: true, handlers: { + ...glfmMdastToHastHandlers, ...pick(skipRenderingHandlers, skipRendering), }, }) @@ -99,13 +104,13 @@ const compilerFactory = (renderer) => * tree in any desired representation * * @param {String} params.markdown Markdown to parse - * @param {(tree: MDast -> any)} params.renderer A function that accepts mdast + * @param {Function} params.renderer A function that accepts mdast * AST tree and returns an object of any type that represents the result of * rendering the tree. See the references below to for more information * about MDast. * * MDastTree documentation https://github.com/syntax-tree/mdast - * @returns {Promise<any>} Returns a promise with the result of rendering + * @returns {Promise} Returns a promise with the result of rendering * the MDast tree */ export const render = async ({ markdown, renderer, skipRendering = [] }) => { diff --git a/app/assets/javascripts/lib/gfm/mdast_to_hast_handlers/glfm_mdast_to_hast_handlers.js b/app/assets/javascripts/lib/gfm/mdast_to_hast_handlers/glfm_mdast_to_hast_handlers.js new file mode 100644 index 00000000000..91b09e69405 --- /dev/null +++ b/app/assets/javascripts/lib/gfm/mdast_to_hast_handlers/glfm_mdast_to_hast_handlers.js @@ -0,0 +1 @@ +export const tableOfContents = (h, node) => h(node.position, 'nav'); |