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Fix various mermaid bugs (#36547)

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* Fix #36515
* Fix #23076
* Remove unnecessary `mermaid.parse`
* Fix data race when using `data-render-done`
* Remove unnecessary `Promise.all`
* Fix duplicate `load` event and duplicate SVG node rendering
* Remove unnecessary `IntersectionObserver`
* Add `bindFunctions` call, the old comment seems not true
This commit is contained in:
wxiaoguang 2026-02-08 12:21:11 +08:00 committed by GitHub
parent 49e6d5f6d6
commit a60201a071
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GPG Key ID: B5690EEEBB952194
3 changed files with 74 additions and 94 deletions
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5
web_src/js/markup/codecopy.ts
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@ -1,10 +1,13 @@
import {svg} from '../svg.ts';
import {queryElems} from '../utils/dom.ts';
export function makeCodeCopyButton(): HTMLButtonElement {
export function makeCodeCopyButton(attrs: Record<string, string> = {}): HTMLButtonElement {
const button = document.createElement('button');
button.classList.add('code-copy', 'ui', 'button');
button.innerHTML = svg('octicon-copy');
for (const [key, value] of Object.entries(attrs)) {
button.setAttribute(key, value);
}
return button;
}

32
web_src/js/markup/mermaid.test.ts
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@ -1,37 +1,37 @@
import {sourcesContainElk} from './mermaid.ts';
import {sourceNeedsElk} from './mermaid.ts';
import {dedent} from '../utils/testhelper.ts';
test('sourcesContainElk', () => {
expect(sourcesContainElk([dedent(`
test('MermaidConfigLayoutCheck', () => {
expect(sourceNeedsElk(dedent(`
flowchart TB
elk --> B
`)])).toEqual(false);
`))).toEqual(false);
expect(sourcesContainElk([dedent(`
expect(sourceNeedsElk(dedent(`
---
config:
layout : elk
---
flowchart TB
A --> B
`)])).toEqual(true);
`))).toEqual(true);
expect(sourcesContainElk([dedent(`
expect(sourceNeedsElk(dedent(`
---
config:
layout: elk.layered
---
flowchart TB
A --> B
`)])).toEqual(true);
`))).toEqual(true);
expect(sourcesContainElk([`
expect(sourceNeedsElk(`
%%{ init : { "flowchart": { "defaultRenderer": "elk" } } }%%
flowchart TB
A --> B
`])).toEqual(true);
`)).toEqual(true);
expect(sourcesContainElk([`
expect(sourceNeedsElk(dedent(`
---
config:
layout: 123
@ -39,21 +39,21 @@ test('sourcesContainElk', () => {
%%{ init : { "class": { "defaultRenderer": "elk.any" } } }%%
flowchart TB
A --> B
`])).toEqual(true);
`))).toEqual(true);
expect(sourcesContainElk([`
expect(sourceNeedsElk(`
%%{init:{
"layout" : "elk.layered"
}}%%
flowchart TB
A --> B
`])).toEqual(true);
`)).toEqual(true);
expect(sourcesContainElk([`
expect(sourceNeedsElk(`
%%{ initialize: {
'layout' : 'elk.layered'
}}%%
flowchart TB
A --> B
`])).toEqual(true);
`)).toEqual(true);
});

131
web_src/js/markup/mermaid.ts
View File

@ -1,7 +1,7 @@
import {isDarkTheme} from '../utils.ts';
import {isDarkTheme, parseDom} from '../utils.ts';
import {makeCodeCopyButton} from './codecopy.ts';
import {displayError} from './common.ts';
import {queryElems} from '../utils/dom.ts';
import {createElementFromAttrs, queryElems} from '../utils/dom.ts';
import {html, htmlRaw} from '../utils/html.ts';
import {load as loadYaml} from 'js-yaml';
import type {MermaidConfig} from 'mermaid';
@ -58,29 +58,18 @@ function configContainsElk(config: MermaidConfig | null) {
// * config.{any-diagram-config}.defaultRenderer
// Although only a few diagram types like "flowchart" support "defaultRenderer",
// as long as there is no side effect, here do a general check for all properties of "config", for ease of maintenance
return configValueIsElk(config.layout) || Object.values(config).some((value) => configValueIsElk(value?.defaultRenderer));
return configValueIsElk(config.layout) || Object.values(config).some((diagCfg) => configValueIsElk(diagCfg?.defaultRenderer));
}
/** detect whether mermaid sources contain elk layout configuration */
export function sourcesContainElk(sources: Array<string>) {
for (const source of sources) {
if (isSourceTooLarge(source)) continue;
const yamlConfig = parseYamlInitConfig(source);
if (configContainsElk(yamlConfig)) return true;
const jsonConfig = parseJsonInitConfig(source);
if (configContainsElk(jsonConfig)) return true;
}
return false;
export function sourceNeedsElk(source: string) {
if (isSourceTooLarge(source)) return false;
const configYaml = parseYamlInitConfig(source), configJson = parseJsonInitConfig(source);
return configContainsElk(configYaml) || configContainsElk(configJson);
}
async function loadMermaid(sources: Array<string>) {
async function loadMermaid(needElkRender: boolean) {
const mermaidPromise = import(/* webpackChunkName: "mermaid" */'mermaid');
const elkPromise = sourcesContainElk(sources) ?
import(/* webpackChunkName: "mermaid-layout-elk" */'@mermaid-js/layout-elk') : null;
const elkPromise = needElkRender ? import(/* webpackChunkName: "mermaid-layout-elk" */'@mermaid-js/layout-elk') : null;
const results = await Promise.all([mermaidPromise, elkPromise]);
return {
mermaid: results[0].default,
@ -92,86 +81,74 @@ let elkLayoutsRegistered = false;
export async function initMarkupCodeMermaid(elMarkup: HTMLElement): Promise<void> {
// .markup code.language-mermaid
const els = Array.from(queryElems(elMarkup, 'code.language-mermaid'));
if (!els.length) return;
const sources = Array.from(els, (el) => el.textContent ?? '');
const {mermaid, elkLayouts} = await loadMermaid(sources);
const mermaidBlocks: Array<{source: string, parentContainer: HTMLElement}> = [];
const attrMermaidRendered = 'data-markup-mermaid-rendered';
let needElkRender = false;
for (const elCodeBlock of queryElems(elMarkup, 'code.language-mermaid')) {
const parentContainer = elCodeBlock.closest('pre')!; // it must exist, if no, there must be a bug
if (parentContainer.hasAttribute(attrMermaidRendered)) continue;
parentContainer.setAttribute(attrMermaidRendered, 'true');
const source = elCodeBlock.textContent ?? '';
needElkRender = needElkRender || sourceNeedsElk(source);
mermaidBlocks.push({source, parentContainer});
}
if (!mermaidBlocks.length) return;
const {mermaid, elkLayouts} = await loadMermaid(needElkRender);
if (elkLayouts && !elkLayoutsRegistered) {
mermaid.registerLayoutLoaders(elkLayouts);
elkLayoutsRegistered = true;
}
mermaid.initialize({
startOnLoad: false,
theme: isDarkTheme() ? 'dark' : 'neutral',
theme: isDarkTheme() ? 'dark' : 'neutral', // TODO: maybe it should use "darkMode" to adopt more user-specified theme instead of just "dark" or "neutral"
securityLevel: 'strict',
suppressErrorRendering: true,
});
await Promise.all(els.map(async (el, index) => {
const source = sources[index];
const pre = el.closest('pre');
if (!pre || pre.hasAttribute('data-render-done')) {
return;
}
// mermaid is a globally shared instance, its document also says "Multiple calls to this function will be enqueued to run serially."
// so here we just simply render the mermaid blocks one by one, no need to do "Promise.all" concurrently
for (const block of mermaidBlocks) {
const {source, parentContainer} = block;
if (isSourceTooLarge(source)) {
displayError(pre, new Error(`Mermaid source of ${source.length} characters exceeds the maximum allowed length of ${mermaidMaxSourceCharacters}.`));
return;
displayError(parentContainer, new Error(`Mermaid source of ${source.length} characters exceeds the maximum allowed length of ${mermaidMaxSourceCharacters}.`));
continue;
}
try {
await mermaid.parse(source);
} catch (err) {
displayError(pre, err);
return;
}
try {
// can't use bindFunctions here because we can't cross the iframe boundary. This
// means js-based interactions won't work but they aren't intended to work either
const {svg} = await mermaid.render('mermaid', source);
// render the mermaid diagram to svg text, and parse it to a DOM node
const {svg: svgText, bindFunctions} = await mermaid.render('mermaid', source, parentContainer);
const svgDoc = parseDom(svgText, 'image/svg+xml');
const svgNode = (svgDoc.documentElement as unknown) as SVGSVGElement;
// create an iframe to sandbox the svg with styles, and set correct height by reading svg's viewBox height
const iframe = document.createElement('iframe');
iframe.classList.add('markup-content-iframe', 'tw-invisible');
iframe.srcdoc = html`<html><head><style>${htmlRaw(iframeCss)}</style></head><body>${htmlRaw(svg)}</body></html>`;
iframe.classList.add('markup-content-iframe', 'is-loading');
iframe.srcdoc = html`<html><head><style>${htmlRaw(iframeCss)}</style></head><body></body></html>`;
const mermaidBlock = document.createElement('div');
mermaidBlock.classList.add('mermaid-block', 'is-loading', 'tw-hidden');
mermaidBlock.append(iframe);
const btn = makeCodeCopyButton();
btn.setAttribute('data-clipboard-text', source);
mermaidBlock.append(btn);
const updateIframeHeight = () => {
const body = iframe.contentWindow?.document?.body;
if (body) {
iframe.style.height = `${body.clientHeight}px`;
}
};
// although the "viewBox" is optional, mermaid's output should always have a correct viewBox with width and height
const iframeHeightFromViewBox = Math.ceil(svgNode.viewBox?.baseVal?.height ?? 0);
if (iframeHeightFromViewBox) iframe.style.height = `${iframeHeightFromViewBox}px`;
// the iframe will be fully reloaded if its DOM context is changed (e.g.: moved in the DOM tree).
// to avoid unnecessary reloading, we should insert the iframe to its final position only once.
iframe.addEventListener('load', () => {
pre.replaceWith(mermaidBlock);
mermaidBlock.classList.remove('tw-hidden');
updateIframeHeight();
setTimeout(() => { // avoid flash of iframe background
mermaidBlock.classList.remove('is-loading');
iframe.classList.remove('tw-invisible');
}, 0);
// same origin, so we can operate "iframe body" and all elements directly
const iframeBody = iframe.contentDocument!.body;
iframeBody.append(svgNode);
bindFunctions?.(iframeBody); // follow "mermaid.render" doc, attach event handlers to the svg's container
// update height when element's visibility state changes, for example when the diagram is inside
// a <details> + <summary> block and the <details> block becomes visible upon user interaction, it
// would initially set a incorrect height and the correct height is set during this callback.
(new IntersectionObserver(() => {
updateIframeHeight();
}, {root: document.documentElement})).observe(iframe);
// according to mermaid, the viewBox height should always exist, here just a fallback for unknown cases.
// and keep in mind: clientHeight can be 0 if the element is hidden (display: none).
if (!iframeHeightFromViewBox && iframeBody.clientHeight) iframe.style.height = `${iframeBody.clientHeight}px`;
iframe.classList.remove('is-loading');
});
document.body.append(mermaidBlock);
const container = createElementFromAttrs('div', {class: 'mermaid-block'}, iframe, makeCodeCopyButton({'data-clipboard-text': source}));
parentContainer.replaceWith(container);
} catch (err) {
displayError(pre, err);
displayError(parentContainer, err);
}
}));
}
}