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    mdast-zone
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    5.1.1 • Public • Published

    mdast-zone

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    mdast utility to find two comments and replace the content in them.

    Contents

    What is this?

    This package is a utility that lets you find certain comments, then takes the content between them, and calls a given handler with the result, so that you can change or replace things.

    When should I use this?

    This utility is typically useful when you have certain sections that can be generated. Comments are a hidden part of markdown, so they can be used as processing instructions. You can use those comments to define what content to change or replace.

    A similar package, mdast-util-heading-range, does the same but uses a heading to mark the start and end of sections.

    Install

    This package is ESM only. In Node.js (version 14.14+ and 16.0+), install with npm:

    npm install mdast-zone

    In Deno with esm.sh:

    import {zone} from 'https://esm.sh/mdast-zone@5'

    In browsers with esm.sh:

    <script type="module">
      import {zone} from 'https://esm.sh/mdast-zone@5?bundle'
    </script>

    Use

    Say we have the following file, example.md:

    <!--foo start-->
    
    Foo
    
    <!--foo end-->

    …and a module example.js:

    import {read} from 'to-vfile'
    import {remark} from 'remark'
    import {zone} from 'mdast-zone'
    
    const file = await remark()
      .use(myPluginThatReplacesFoo)
      .process(await read('example.md'))
    
    console.log(String(file))
    
    /** @type {import('unified').Plugin<[], import('mdast').Root>} */
    function myPluginThatReplacesFoo() {
      return (tree) => {
        zone(tree, 'foo', (start, nodes, end) => [
          start,
          {type: 'paragraph', children: [{type: 'text', value: 'Bar.'}]},
          end
        ])
      }
    }

    …now running node example.js yields:

    <!--foo start-->
    
    Bar.
    
    <!--foo end-->

    API

    This package exports the identifier zone. There is no default export.

    zone(tree, name, handler)

    Search tree for a start and end comments matching name and change their “section” with handler.

    Parameters
    • tree (Node) — tree to change
    • name (string) — comment name to look for
    • handler (Handler) — handle a section
    Returns

    Nothing (void).

    Handler

    Callback called when a section is found (TypeScript type).

    Parameters
    • start (Node) — start of section
    • nodes (Array<Node>) — nodes between start and end
    • end (Node) — end of section
    • info (Info) — extra info
    Returns

    Results (Array<Node | null | undefined>, optional).

    If nothing is returned, nothing will be changed. If an array of nodes (can include null and undefined) is returned, the original section will be replaced by those nodes.

    Info

    Extra info (TypeScript type).

    Fields
    • parent (Node) — parent of the section
    • start (number) — index of start in parent
    • end (number or null) — index of end in parent

    Types

    This package is fully typed with TypeScript. It exports the additional types Handler and Info.

    Compatibility

    Projects maintained by the unified collective are compatible with all maintained versions of Node.js. As of now, that is Node.js 14.14+ and 16.0+. Our projects sometimes work with older versions, but this is not guaranteed.

    Security

    Improper use of handler can open you up to a cross-site scripting (XSS) attack as the value it returns is injected into the syntax tree. This can become a problem if the tree is later transformed to hast. The following example shows how a script is injected that could run when loaded in a browser.

    function handler(start, nodes, end) {
      return [start, {type: 'html', value: '<script>alert(1)</script>'}, end]
    }

    Yields:

    <!--foo start-->
    
    <script>alert(1)</script>
    
    <!--foo end-->

    Either do not use user input or use hast-util-santize.

    Related

    Contribute

    See contributing.md in syntax-tree/.github for ways to get started. See support.md for ways to get help.

    This project has a code of conduct. By interacting with this repository, organization, or community you agree to abide by its terms.

    License

    MIT © Titus Wormer

    Install

    npm i mdast-zone

    DownloadsWeekly Downloads

    5,073

    Version

    5.1.1

    License

    MIT

    Unpacked Size

    15.2 kB

    Total Files

    7

    Last publish

    Collaborators

    • wooorm
    • kmck