Add browser support

.c8rc.json

@@ -1,4 +1,5 @@
 {
   "100": true,
+  "include": ["index.ts"],
   "reporter": ["html", "lcov", "text"]
 }

.eslintrc.yaml

@@ -1,2 +1,7 @@
 extends:
   - remcohaszing
+rules:
+  no-param-reassign: off
+  '@typescript-eslint/consistent-type-imports':
+    - error
+    - prefer: type-imports

.github/workflows/ci.yml

@@ -43,6 +43,7 @@ jobs:
       - run: npm --global install npm@8
         if: ${{ matrix.node-version == 14 }}
       - run: npm ci
+      - run: npx playwright install
       - run: npm test
       - uses: codecov/codecov-action@v3
         if: ${{ matrix.node-version == 18 }}

.gitignore

@@ -1,6 +1,7 @@
 coverage/
 dist/
 node_modules/
+test-results/
 *.d.ts
 *.js
 *.log

.prettierignore

@@ -1,4 +1,3 @@
-__fixtures__/*/output.md
-__snapshots__/
+**/*-snapshots/*
 coverage/
 dist/

README.md

@@ -48,15 +48,22 @@ console.log(value);
 These options are passed to
 [`puppeteer.launch()`](https://pptr.dev/#?product=Puppeteer&show=api-puppeteerlaunchoptions).
 
+- **Note**: This options is required in Node.js. In the browser this option is unused.
+
 #### `svgo`
 
 These options are passed to the [SVGO](https://github.com/svg/svgo) constructor. Set to `null` to
 disable minifying using SVGO completely.
 
+**Note**: This options is only supported in Node.js. In the browser this option is unused.
+
 #### `mermaidOptions`
 
 The [mermaid options](https://mermaid-js.github.io/mermaid/#/Setup) to use.
 
+**Note**: This options is only supported in Node.js. In the browser this option is unused. If you
+use this in a browser, call `mermaid.initialize()` manually.
+
 ## License
 
 [MIT](LICENSE.md) © [Remco Haszing](https://github.com/remcohaszing)

browser.ts

@@ -0,0 +1,39 @@
+import { fromDom } from 'hast-util-from-dom';
+import { type Code, type Parent, type Root } from 'mdast';
+import mermaid from 'mermaid';
+import { type Plugin } from 'unified';
+import { visit } from 'unist-util-visit';
+
+// eslint-disable-next-line jsdoc/require-jsdoc
+function transformer(ast: Root): void {
+  const instances: [string, number, Parent][] = [];
+
+  visit(ast, { type: 'code', lang: 'mermaid' }, (node: Code, index, parent: Parent) => {
+    instances.push([node.value, index, parent]);
+  });
+
+  // Nothing to do. No need to start puppeteer in this case.
+  if (!instances.length) {
+    return;
+  }
+
+  const results = instances.map(([code], index) =>
+    // @ts-expect-error The mermaid types are wrong.
+    mermaid.render(`remark-mermaid-${index}`, code),
+  );
+
+  const wrapper = document.createElement('div');
+  for (const [i, [, index, parent]] of instances.entries()) {
+    const value = results[i];
+    wrapper.innerHTML = value;
+    parent.children.splice(index, 1, {
+      type: 'paragraph',
+      children: [{ type: 'html', value }],
+      data: { hChildren: [fromDom(wrapper.firstChild!)] },
+    });
+  }
+}
+
+const remarkMermaid: Plugin<[], Root> = () => transformer;
+
+export default remarkMermaid;

index.ts

@@ -1,12 +1,12 @@
 import { createRequire } from 'module';
 
 import { fromParse5 } from 'hast-util-from-parse5';
-import { Code, Parent, Root } from 'mdast';
-import { Mermaid } from 'mermaid';
+import { type Code, type Parent, type Root } from 'mdast';
+import { type Mermaid } from 'mermaid';
 import { parseFragment } from 'parse5';
-import puppeteer, { Browser, Page, PuppeteerLaunchOptions } from 'puppeteer-core';
-import { optimize, OptimizedSvg, OptimizeOptions } from 'svgo';
-import { Plugin } from 'unified';
+import puppeteer, { type Browser, type Page, type PuppeteerLaunchOptions } from 'puppeteer-core';
+import { optimize, type OptimizedSvg, type OptimizeOptions } from 'svgo';
+import { type Plugin } from 'unified';
 import { visit } from 'unist-util-visit';
 
 const mermaidScript = {
@@ -76,7 +76,9 @@ export const defaultSVGOOptions: OptimizeOptions = {
 
 export interface RemarkMermaidOptions {
   /**
-   * Launc options to pass to puppeteer.
+   * Launch options to pass to puppeteer.
+   *
+   * **Note**: This options is required in Node.js. In the browser this option is unused.
    */
   launchOptions: PuppeteerLaunchOptions;
 
@@ -85,24 +87,31 @@ export interface RemarkMermaidOptions {
    *
    * Set to `null` explicitly to disable this.
    *
+   * **Note**: This options is only supported in Node.js. In the browser this option is unused.
+   *
    * @default defaultSVGOOptions
    */
   svgo?: OptimizeOptions | null;
 
   /**
    * The mermaid options to use.
+   *
+   * **Note**: This options is only supported in Node.js. In the browser this option is unused. If
+   * you use this in a browser, call `mermaid.initialize()` manually.
    */
   mermaidOptions?: Parameters<typeof mermaid['initialize']>[0];
 }
 
 /**
  * @param options Options that may be used to tweak the output.
  */
-const remarkMermaid: Plugin<[RemarkMermaidOptions], Root> = ({
-  launchOptions,
-  mermaidOptions = {},
-  svgo = defaultSVGOOptions,
-}) => {
+const remarkMermaid: Plugin<[RemarkMermaidOptions?], Root> = (options) => {
+  if (!options?.launchOptions?.executablePath) {
+    throw new Error('The option `launchOptions.executablePath` is required when using Node.js');
+  }
+
+  const { launchOptions, mermaidOptions, svgo = defaultSVGOOptions } = options;
+
   let browserPromise: Promise<Browser> | undefined;
   let count = 0;
 
@@ -135,14 +144,17 @@ const remarkMermaid: Plugin<[RemarkMermaidOptions], Root> = ({
       results = await page.evaluate(
         // We can’t calculate coverage on this function, as it’s run by Chrome, not Node.
         /* c8 ignore start */
-        (codes, initOptions) =>
-          codes.map((code) => {
-            const id = 'a';
+        (codes, initOptions) => {
+          if (initOptions) {
             mermaid.initialize(initOptions);
+          }
+          return codes.map((code) => {
+            const id = 'a';
             const div = document.createElement('div');
             div.innerHTML = mermaid.render(id, code);
             return div.innerHTML;
-          }),
+          });
+        },
         /* C8 ignore stop */
         instances.map((instance) => instance[0]),
         mermaidOptions,