markdown-it-link-attributes/README.md

A markdown-it plugin to configure the attributes for links

# markdown-it-link-attributes

> Link attributes plugin for [markdown-it](https://github.com/markdown-it/markdown-it) markdown parser.

## Install

node.js, browser:

```bash
npm install markdown-it-link-attributes --save
bower install markdown-it-link-attributes --save
```

## Use

### Basic Configuration

You can pass an object with an attrs property. Each link parsed with this config will have the passed attributes.

```js
var md = require("markdown-it")();
var mila = require("markdown-it-link-attributes");

md.use(mila, {
  attrs: {
    target: "_blank",
    rel: "noopener",
  },
});

var result = md.render("[Example](https://example.com");

result; // <a href="https://example.com" target="_blank" rel="noopener">Example</a>
```

If the `linkify` option is set to `true` on `markdown-it`, then the attributes will be applied to plain links as well.

```js
var md = require("markdown-it")({
  linkify: true,
});

md.use(mila, {
  target: "_blank",
  rel: "noopener",
});

var html = md.render("foo https://google.com bar");
html; // <p>foo <a href="https://google.com" target="_blank" rel="noopener">https://google.com</a> bar</p>
```

### Applying classes

You can apply a `class` to a link by using a `class` or a `className` property. Either one will work, but use only one, not both.

```js
md.use(mila, {
  attrs: {
    class: "my-class",
  },
});

// or
md.use(mila, {
  attrs: {
    className: "my-class",
  },
});
```

### Conditionally apply attributes

You can choose to test a link's `href` against a matcher function. The attributes will be applied only if the matcher function returns true.

```js
md.use(mila, {
  matcher(href, config) {
    return href.startsWith("https:");
  },
  attrs: {
    target: "_blank",
    rel: "noopener",
  },
});

var matchingResult = md.render("[Matching Example](https://example.com");
var ignoredResult = md.render("[Not Matching Example](http://example.com");

matchingResult; // <a href="https://example.com" target="_blank" rel="noopener">Matching Example</a>
ignoredResult; // <a href="http://example.com">Not Matching Example</a>
```

### Multiple Configurations

Alternatively, you can pass an Array of configurations. The first matcher function to return true will be applied to the link.

```js
md.use(mila, [
  {
    matcher(href) {
      return href.match(/^https?:\/\//);
    },
    attrs: {
      class: "external-link",
    },
  },
  {
    matcher(href) {
      return href.startsWith("/");
    },
    attrs: {
      class: "absolute-link",
    },
  },
  {
    matcher(href) {
      return href.startsWith("/blue/");
    },
    attrs: {
      class: "link-that-contains-the-word-blue",
    },
  },
]);

var externalResult = md.render("[external](https://example.com");
var absoluteResult = md.render("[absolute](/some-page");
var blueResult = md.render("[blue](relative/link/with/blue/in/the/name");

externalResult; // <a href="https://example.com" class="external-link">external</a>
absoluteResult; // <a href="/some-page" class="absolute-link">absolute</a>
blueResult; // <a href="relative/link/with/blue/in/the/name" class="link-that-contains-the-word-blue">blue</a>
```

If multiple matcher functions return true, the first configuration to match will be used.

```js
// This matches both the "starts with http or https" rule and the "contains the word blue" rule.
// Since the http/https rule was defined first, that is the configuration that is used.
var result = md.render("[external](https://example.com/blue");

result; // <a href="https://example.com/blue" class="external-link">external</a>
```

## Usage in the browser

_Differences in browser._ If you load script directly into the page, without a package system, the module will add itself globally as `window.markdownitLinkAttributes`.
You need to load `dist/markdown-it-link-attributes.min.js`, if you don't use a build system.

## Testing

This plugin is tested against the latest version of markdown-it

## License

[MIT](https://github.com/markdown-it/markdown-it-footnote/blob/master/LICENSE)