1
0
silverbullet/plugs/markdown/markdown_render.ts
2023-11-12 12:08:09 +01:00

473 lines
11 KiB
TypeScript

import {
addParentPointers,
collectNodesOfType,
findNodeOfType,
ParseTree,
renderToText,
traverseTree,
} from "$sb/lib/tree.ts";
import { Fragment, renderHtml, Tag } from "./html_render.ts";
export type MarkdownRenderOptions = {
failOnUnknown?: true;
smartHardBreak?: true;
annotationPositions?: true;
attachmentUrlPrefix?: string;
preserveAttributes?: true;
// When defined, use to inline images as data: urls
translateUrls?: (url: string) => string;
};
function cleanTags(values: (Tag | null)[], cleanWhitespace = false): Tag[] {
const result: Tag[] = [];
for (const value of values) {
if (cleanWhitespace && typeof value === "string" && value.match(/^\s+$/)) {
continue;
}
if (value) {
result.push(value);
}
}
return result;
}
function preprocess(t: ParseTree, options: MarkdownRenderOptions = {}) {
addParentPointers(t);
traverseTree(t, (node) => {
if (!node.type) {
if (node.text?.startsWith("\n")) {
const prevNodeIdx = node.parent!.children!.indexOf(node) - 1;
if (node.parent!.children![prevNodeIdx]?.type !== "Paragraph") {
node.text = node.text.slice(1);
}
}
}
return false;
});
}
function posPreservingRender(
t: ParseTree,
options: MarkdownRenderOptions = {},
): Tag | null {
const tag = render(t, options);
if (!options.annotationPositions) {
return tag;
}
if (!tag) {
return null;
}
if (typeof tag === "string") {
return tag;
}
if (t.from) {
if (!tag.attrs) {
tag.attrs = {};
}
tag.attrs["data-pos"] = "" + t.from;
}
return tag;
}
function render(
t: ParseTree,
options: MarkdownRenderOptions = {},
): Tag | null {
if (t.type?.endsWith("Mark") || t.type?.endsWith("Delimiter")) {
return null;
}
switch (t.type) {
case "Document":
return {
name: Fragment,
body: cleanTags(mapRender(t.children!)),
};
case "FrontMatter":
return null;
case "CommentBlock":
// Remove, for now
return null;
case "ATXHeading1":
return {
name: "h1",
body: cleanTags(mapRender(t.children!)),
};
case "ATXHeading2":
return {
name: "h2",
body: cleanTags(mapRender(t.children!)),
};
case "ATXHeading3":
return {
name: "h3",
body: cleanTags(mapRender(t.children!)),
};
case "ATXHeading4":
return {
name: "h4",
body: cleanTags(mapRender(t.children!)),
};
case "ATXHeading5":
return {
name: "h5",
body: cleanTags(mapRender(t.children!)),
};
case "Paragraph":
return {
name: "span",
attrs: {
class: "p",
},
body: cleanTags(mapRender(t.children!)),
};
// Code blocks
case "FencedCode":
case "CodeBlock": {
// Clear out top-level indent blocks
const lang = findNodeOfType(t, "CodeInfo");
t.children = t.children!.filter((c) => c.type);
return {
name: "pre",
attrs: {
"data-lang": lang ? lang.children![0].text : undefined,
},
body: cleanTags(mapRender(t.children!)),
};
}
case "CodeInfo":
return null;
case "CodeText":
return t.children![0].text!;
case "Blockquote":
return {
name: "blockquote",
body: cleanTags(mapRender(t.children!)),
};
case "HardBreak":
return {
name: "br",
body: "",
};
// Basic styling
case "Emphasis":
return {
name: "em",
body: cleanTags(mapRender(t.children!)),
};
case "Highlight":
return {
name: "span",
attrs: {
class: "highlight",
},
body: cleanTags(mapRender(t.children!)),
};
case "Strikethrough":
return {
name: "del",
body: cleanTags(mapRender(t.children!)),
};
case "InlineCode":
return {
name: "tt",
body: cleanTags(mapRender(t.children!)),
};
case "BulletList":
return {
name: "ul",
body: cleanTags(mapRender(t.children!), true),
};
case "OrderedList":
return {
name: "ol",
body: cleanTags(mapRender(t.children!), true),
};
case "ListItem":
return {
name: "li",
body: cleanTags(mapRender(t.children!), true),
};
case "StrongEmphasis":
return {
name: "strong",
body: cleanTags(mapRender(t.children!)),
};
case "HorizontalRule":
return {
name: "hr",
body: "",
};
case "Link": {
const linkText = t.children![1].text!;
const urlNode = findNodeOfType(t, "URL");
if (!urlNode) {
return renderToText(t);
}
let url = urlNode.children![0].text!;
if (url.indexOf("://") === -1) {
url = `${options.attachmentUrlPrefix || ""}${url}`;
}
return {
name: "a",
attrs: {
href: url,
},
body: linkText,
};
}
case "Image": {
const altText = t.children![1].text!;
const urlNode = findNodeOfType(t, "URL");
if (!urlNode) {
return renderToText(t);
}
let url = urlNode!.children![0].text!;
if (url.indexOf("://") === -1) {
url = `${options.attachmentUrlPrefix || ""}${url}`;
}
return {
name: "img",
attrs: {
src: url,
alt: altText,
},
body: "",
};
}
// Custom stuff
case "WikiLink": {
// console.log("WikiLink", JSON.stringify(t, null, 2));
const ref = findNodeOfType(t, "WikiLinkPage")!.children![0].text!;
let linkText = ref.split("/").pop()!;
const aliasNode = findNodeOfType(t, "WikiLinkAlias");
if (aliasNode) {
linkText = aliasNode.children![0].text!;
}
return {
name: "a",
attrs: {
href: `/${ref.replace("@", "#")}`,
class: "wiki-link",
"data-ref": ref,
},
body: linkText,
};
}
case "NakedURL": {
const url = t.children![0].text!;
return {
name: "a",
attrs: {
href: url,
},
body: url,
};
}
case "Hashtag":
return {
name: "strong",
body: t.children![0].text!,
};
case "Task": {
let externalTaskRef = "";
collectNodesOfType(t, "WikiLinkPage").forEach((wikilink) => {
const ref = wikilink.children![0].text!;
if (!externalTaskRef && (ref.includes("@") || ref.includes("$"))) {
externalTaskRef = ref;
}
});
return {
name: "span",
attrs: externalTaskRef
? {
"data-external-task-ref": externalTaskRef,
}
: {},
body: cleanTags(mapRender(t.children!)),
};
}
case "TaskState": {
// child[0] = marker, child[1] = state, child[2] = marker
const stateText = t.children![1].text!;
if ([" ", "x", "X"].includes(stateText)) {
return {
name: "input",
attrs: {
type: "checkbox",
checked: stateText !== " " ? "checked" : undefined,
"data-state": stateText,
},
body: "",
};
} else {
return {
name: "span",
attrs: {
class: "task-state",
},
body: stateText,
};
}
}
case "NamedAnchor":
return {
name: "a",
attrs: {
name: t.children![0].text?.substring(1),
},
body: "",
};
case "CommandLink": {
// Child 0 is CommandLinkMark, child 1 is CommandLinkPage
const commandText = t.children![1].children![0].text!;
return {
name: "button",
attrs: {
"data-onclick": JSON.stringify(["command", commandText]),
},
body: commandText,
};
}
case "DeadlineDate":
return {
name: "span",
attrs: {
class: "task-deadline",
},
body: renderToText(t),
};
// Tables
case "Table":
return {
name: "table",
body: cleanTags(mapRender(t.children!)),
};
case "TableHeader":
return {
name: "thead",
body: [
{
name: "tr",
body: cleanTags(mapRender(t.children!)),
},
],
};
case "TableCell":
return {
name: "td",
body: cleanTags(mapRender(t.children!)),
};
case "TableRow": {
const children = t.children!;
const newChildren: ParseTree[] = [];
// Ensure there is TableCell in between every delimiter
let lookingForCell = false;
for (const child of children) {
if (child.type === "TableDelimiter" && lookingForCell) {
// We were looking for a cell, but didn't fine one: empty cell!
// Let's inject an empty one
newChildren.push({
type: "TableCell",
children: [],
});
}
if (child.type === "TableDelimiter") {
lookingForCell = true;
}
if (child.type === "TableCell") {
lookingForCell = false;
}
newChildren.push(child);
}
return {
name: "tr",
body: cleanTags(mapRender(newChildren)),
};
}
case "Directive": {
const body = findNodeOfType(t, "DirectiveBody")!;
return posPreservingRender(body.children![0], options);
}
case "Attribute":
if (options.preserveAttributes) {
return {
name: "span",
attrs: {
class: "attribute",
},
body: renderToText(t),
};
}
return null;
case "Escape": {
return {
name: "span",
attrs: {
class: "escape",
},
body: t.children![0].text!.slice(1),
};
}
// Text
case undefined:
return t.text!;
default:
if (options.failOnUnknown) {
console.error("Not handling", JSON.stringify(t, null, 2));
throw new Error(`Unknown markdown node type ${t.type}`);
} else {
// Falling back to rendering verbatim
console.warn("Not handling", JSON.stringify(t, null, 2));
return renderToText(t);
}
}
function mapRender(children: ParseTree[]) {
return children.map((t) => posPreservingRender(t, options));
}
}
function traverseTag(
t: Tag,
fn: (t: Tag) => void,
) {
fn(t);
if (typeof t === "string") {
return;
}
if (t.body) {
for (const child of t.body) {
traverseTag(child, fn);
}
}
}
export function renderMarkdownToHtml(
t: ParseTree,
options: MarkdownRenderOptions = {},
) {
preprocess(t, options);
const htmlTree = posPreservingRender(t, options);
if (htmlTree && options.translateUrls) {
traverseTag(htmlTree, (t) => {
if (typeof t === "string") {
return;
}
if (t.name === "img") {
t.attrs!.src = options.translateUrls!(t.attrs!.src!);
}
if (t.name === "a" && t.attrs!.href) {
t.attrs!.href = options.translateUrls!(t.attrs!.href);
}
});
}
return renderHtml(htmlTree);
}