94 lines
2.8 KiB
JavaScript
94 lines
2.8 KiB
JavaScript
import flash from '~/flash';
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import { sprintf, __ } from '../../locale';
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// Renders diagrams and flowcharts from text using Mermaid in any element with the
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// `js-render-mermaid` class.
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//
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// Example markup:
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//
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// <pre class="js-render-mermaid">
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// graph TD;
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// A-- > B;
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// A-- > C;
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// B-- > D;
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// C-- > D;
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// </pre>
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//
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// This is an arbitrary number; Can be iterated upon when suitable.
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const MAX_CHAR_LIMIT = 5000;
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export default function renderMermaid($els) {
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if (!$els.length) return;
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import(/* webpackChunkName: 'mermaid' */ 'mermaid')
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.then(mermaid => {
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mermaid.initialize({
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// mermaid core options
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mermaid: {
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startOnLoad: false,
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},
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// mermaidAPI options
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theme: 'neutral',
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flowchart: {
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htmlLabels: false,
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},
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securityLevel: 'strict',
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});
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let renderedChars = 0;
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$els.each((i, el) => {
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// Mermaid doesn't like `<br />` tags, so collapse all like tags into `<br>`, which is parsed correctly.
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const source = el.textContent.replace(/<br\s*\/>/g, '<br>');
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/**
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* Restrict the rendering to a certain amount of character to
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* prevent mermaidjs from hanging up the entire thread and
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* causing a DoS.
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*/
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if ((source && source.length > MAX_CHAR_LIMIT) || renderedChars > MAX_CHAR_LIMIT) {
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el.textContent = sprintf(
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__(
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'Cannot render the image. Maximum character count (%{charLimit}) has been exceeded.',
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),
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{ charLimit: MAX_CHAR_LIMIT },
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);
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return;
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}
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renderedChars += source.length;
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// Remove any extra spans added by the backend syntax highlighting.
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Object.assign(el, { textContent: source });
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mermaid.init(undefined, el, id => {
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const svg = document.getElementById(id);
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// As of https://github.com/knsv/mermaid/commit/57b780a0d,
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// Mermaid will make two init callbacks:one to initialize the
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// flow charts, and another to initialize the Gannt charts.
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// Guard against an error caused by double initialization.
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if (svg.classList.contains('mermaid')) {
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return;
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}
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svg.classList.add('mermaid');
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// pre > code > svg
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svg.closest('pre').replaceWith(svg);
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// We need to add the original source into the DOM to allow Copy-as-GFM
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// to access it.
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const sourceEl = document.createElement('text');
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sourceEl.classList.add('source');
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sourceEl.setAttribute('display', 'none');
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sourceEl.textContent = source;
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svg.appendChild(sourceEl);
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});
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});
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})
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.catch(err => {
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flash(`Can't load mermaid module: ${err}`);
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});
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}
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