marked/docs/USING_ADVANCED.md

## The `parse` function

```js
import { marked } from 'marked';
marked.parse(markdownString [,options])
```

|Argument                      |Type    |Notes                                                           |
|:-----------------------------|:-------|:---------------------------------------------------------------|
|markdownString                |`string`|String of markdown source to be compiled.                       |
|<a href="#options">options</a>|`object`|Hash of options. Can also use `marked.use` to set global options|

### Alternative using reference

```js
// Create reference instance
import { marked } from 'marked';

// Set options
marked.use({
  async: true,
  pedantic: false,
  gfm: true,
});

// Compile
console.log(marked.parse(markdownString));
```

<h2 id="options">Options</h2>

|Member      |Type      |Default  |Since    |Notes         |
|:-----------|:---------|:--------|:--------|:-------------|
|async       |`boolean` |`false`  |4.1.0    |If true, `walkTokens` functions can be async and `marked.parse` will return a promise that resolves when all walk tokens functions resolve.|
|breaks      |`boolean` |`false`  |v0.2.7   |If true, add `<br>` on a single line break (copies GitHub behavior on comments, but not on rendered markdown files). Requires `gfm` be `true`.|
|gfm         |`boolean` |`true`   |v0.2.1   |If true, use approved [GitHub Flavored Markdown (GFM) specification](https://github.github.com/gfm/).|
|pedantic    |`boolean` |`false`  |v0.2.1   |If true, conform to the original `markdown.pl` as much as possible. Don't fix original markdown bugs or behavior. Turns off and overrides `gfm`.|
|renderer    |`object`  |`new Renderer()`|v0.3.0|An object containing functions to render tokens to HTML. See [extensibility](/using_pro) for more details.|
|silent      |`boolean` |`false`  |v0.2.7   |If true, the parser does not throw any exception or log any warning. Any error will be returned as a string.|
|tokenizer    |`object`  |`new Tokenizer()`|v1.0.0|An object containing functions to create tokens from markdown. See [extensibility](/using_pro) for more details.|
|walkTokens   |`function`  |`null`|v1.1.0|A function which is called for every token. See [extensibility](/using_pro) for more details.|
|baseUrl (**deprecated**)|`string`  |`null`   |v0.3.9    |Deprecated in v5.0.0 use [`marked-base-url`](https://www.npmjs.com/package/marked-base-url) to prefix url for any relative link. |
|headerIds (**deprecated**)|`boolean` |`true`   |v0.4.0   |Deprecated in v5.0.0 use [`marked-gfm-heading-id`](https://www.npmjs.com/package/marked-gfm-heading-id) to include an `id` attribute when emitting headings (h1, h2, h3, etc).|
|headerPrefix (**deprecated**)|`string`  |`''`     |v0.3.0   |Deprecated in v5.0.0 use [`marked-gfm-heading-id`](https://www.npmjs.com/package/marked-gfm-heading-id) to add a string to prefix the `id` attribute when emitting headings (h1, h2, h3, etc).|
|highlight (**deprecated**)|`function`|`null`   |v0.3.0   |Deprecated in v5.0.0 use [`marked-highlight`](https://www.npmjs.com/package/marked-highlight) to add highlighting to code blocks. |
|langPrefix  (**deprecated**)|`string`  |`'language-'`|v0.3.0|Deprecated in v5.0.0 use [`marked-highlight`](https://www.npmjs.com/package/marked-highlight) to prefix the className in a `<code>` block. Useful for syntax highlighting.|
|mangle (**deprecated**)|`boolean` |`true`   |v0.3.4   |Deprecated in v5.0.0 use [`marked-mangle`](https://www.npmjs.com/package/marked-mangle) to mangle email addresses.|
|sanitize (**deprecated**)|`boolean` |`false`  |v0.2.1   |If true, sanitize the HTML passed into `markdownString` with the `sanitizer` function.<br>**Warning**: This feature is deprecated and it should NOT be used as it cannot be considered secure.<br>Instead use a sanitize library, like [DOMPurify](https://github.com/cure53/DOMPurify) (recommended), [sanitize-html](https://github.com/apostrophecms/sanitize-html) or [insane](https://github.com/bevacqua/insane) on the output HTML! |
|sanitizer  (**deprecated**)|`function`|`null`   |v0.3.4   |A function to sanitize the HTML passed into `markdownString`.|
|smartypants (**deprecated**)|`boolean` |`false`  |v0.2.9   |Deprecated in v5.0.0 use [`marked-smartypants`](https://www.npmjs.com/package/marked-smartypants) to use "smart" typographic punctuation for things like quotes and dashes.|
|xhtml (**deprecated**)|`boolean` |`false`  |v0.3.2   |Deprecated in v5.0.0 use [`marked-xhtml`](https://www.npmjs.com/package/marked-xhtml) to emit self-closing HTML tags for void elements (&lt;br/&gt;, &lt;img/&gt;, etc.) with a "/" as required by XHTML.|

<h2 id="extensions">Known Extensions</h2>

Marked can be extended using [custom extensions](/using_pro#extensions). This is a list of extensions that can be used with `marked.use(extension)`.

<!-- Keep this list ordered alphabetically by name -->

|Name|Package Name|Description|
|:---|:-----------|:----------|
|[Admonition](https://www.npmjs.com/package/marked-admonition-extension)|[`marked-admonition-extension`](https://www.npmjs.com/package/marked-admonition-extension)| Admonition extension |
|[Base URL](https://github.com/markedjs/marked-base-url)|[`marked-base-url`](https://www.npmjs.com/package/marked-base-url)|Prefix relative urls with a base URL.|
|[Bidi](https://github.com/markedjs/marked-bidi)|[`marked-bidi`](https://www.npmjs.com/package/marked-bidi)|Add Bidirectional text support to the HTML|
|[Custom Heading ID](https://github.com/markedjs/marked-custom-heading-id)|[`marked-custom-heading-id`](https://www.npmjs.com/package/marked-custom-heading-id)|Specify a custom heading id in headings with the [Markdown Extended Syntax](https://www.markdownguide.org/extended-syntax/#heading-ids) `# heading {#custom-id}`|
|[Emoji](https://github.com/UziTech/marked-emoji)|[`marked-emoji`](https://www.npmjs.com/package/marked-emoji)|Add emoji support like on GitHub|
|[Extended Tables](https://github.com/calculuschild/marked-extended-tables)|[`marked-extended-tables`](https://www.npmjs.com/package/marked-extended-tables)|Extends the standard Github-Flavored tables to support advanced features: Column Spanning, Row Spanning, Multi-row headers|
|[GFM Heading ID](https://github.com/markedjs/marked-gfm-heading-id)|[`marked-gfm-heading-id`](https://www.npmjs.com/package/marked-gfm-heading-id)|Use [`github-slugger`](https://github.com/Flet/github-slugger) to create the heading IDs and allow a custom prefix.|
|[Highlight](https://github.com/markedjs/marked-highlight)|[`marked-highlight`](https://www.npmjs.com/package/marked-highlight)|Highlight code blocks|
|[Katex Code](https://github.com/UziTech/marked-katex-extension)|[`marked-katex-extension`](https://www.npmjs.com/package/marked-katex-extension)|Render [katex](https://katex.org/) code|
|[LinkifyIt](https://github.com/UziTech/marked-linkify-it)|[`marked-linkify-it`](https://www.npmjs.com/package/marked-linkify-it)|Use [linkify-it](https://github.com/markdown-it/linkify-it) for urls|
|[Mangle](https://github.com/markedjs/marked-mangle)|[`marked-mangle`](https://www.npmjs.com/package/marked-mangle)|Mangle mailto links with HTML character references|
|[Misskey-flavored Markdown](https://akkoma.dev/sfr/marked-mfm)|[`marked-mfm`](https://www.npmjs.com/package/marked-mfm)|Custom extension for [Misskey-flavored Markdown](https://github.com/misskey-dev/mfm.js/blob/develop/docs/syntax.md).|
|[Smartypants](https://github.com/markedjs/marked-smartypants)|[`marked-smartypants`](https://www.npmjs.com/package/marked-smartypants)|Use [smartypants](https://www.npmjs.com/package/smartypants) to use "smart" typographic punctuation for things like quotes and dashes.|
|[XHTML](https://github.com/markedjs/marked-xhtml)|[`marked-xhtml`](https://www.npmjs.com/package/marked-xhtml)|Emit self-closing HTML tags for void elements (&lt;br/&gt;, &lt;img/&gt;, etc.) with a "/" as required by XHTML.|

<h2 id="inline">Inline Markdown</h2>

You can parse inline markdown by running markdown through `marked.parseInline`.

```js
const blockHtml = marked.parse('**strong** _em_');
console.log(blockHtml); // '<p><strong>strong</strong> <em>em</em></p>'

const inlineHtml = marked.parseInline('**strong** _em_');
console.log(inlineHtml); // '<strong>strong</strong> <em>em</em>'
```

<h2 id="highlight">Highlighting</h2>

Use [`marked-highlight`](https://www.npmjs.com/package/marked-highlight) to highlight code blocks.

<h2 id="workers">Workers</h2>

To prevent ReDoS attacks you can run marked on a worker and terminate it when parsing takes longer than usual.

Marked can be run in a [worker thread](https://nodejs.org/api/worker_threads.html) on a node server, or a [web worker](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API) in a browser.

### Node Worker Thread

```js
// markedWorker.js

import { marked } from 'marked';
import { parentPort } from 'worker_threads';

parentPort.on('message', (markdownString) => {
  parentPort.postMessage(marked.parse(markdownString));
});
```

```js
// index.js

import { Worker } from 'worker_threads';
const markedWorker = new Worker('./markedWorker.js');

const markedTimeout = setTimeout(() => {
  markedWorker.terminate();
  throw new Error('Marked took too long!');
}, timeoutLimit);

markedWorker.on('message', (html) => {
  clearTimeout(markedTimeout);
  console.log(html);
  markedWorker.terminate();
});

markedWorker.postMessage(markdownString);
```

### Web Worker

> **NOTE**: Web Workers send the payload from `postMessage` in an object with the payload in a `.data` property

```js
// markedWorker.js

importScripts('path/to/marked.min.js');

onmessage = (e) => {
  const markdownString = e.data
  postMessage(marked.parse(markdownString));
};
```

```js
// script.js

const markedWorker = new Worker('./markedWorker.js');

const markedTimeout = setTimeout(() => {
  markedWorker.terminate();
  throw new Error('Marked took too long!');
}, timeoutLimit);

markedWorker.onmessage = (e) => {
  clearTimeout(markedTimeout);
  const html = e.data;
  console.log(html);
  markedWorker.terminate();
};

markedWorker.postMessage(markdownString);
```
<h2 id="cli-extensions">CLI Extensions</h2>

You can use extensions in the CLI by creating a new CLI that imports marked and the marked binary.

```js
// file: myMarked
#!/usr/bin/node

import { marked } from 'marked';
import customHeadingId from 'marked-custom-heading-id';

marked.use(customHeadingId());

import 'marked/bin/marked';
```

```sh
$ ./myMarked -s "# heading {#custom-id}"
<h1 id="custom-id">heading</h1>
```