How to use Camaro to parse XML to JSON Share postShare icon

A brief guide on XPath

  1. Usage
  2. Text
  3. Text (second level)
  4. Text (all level)
  5. Text (distinct elements)
  6. Attribute
  7. Text (multiple elements)
  8. Text (similar elements, similar sub-entries)
  9. Attribute (multiple elements, multiple sub-entries)

Camaro is a NodeJS library to transform XML to JSON using XPath template format.

Usage

const { transform } = require('camaro')

const parseFeed = async (input) => {
  // Specify input in the 1st parameter, template in the 2nd parameter
  const output = await transform(input, { text: 'feed' })
  console.log(output)
}

parseFeed(`
<feed>foo</feed>
`)

// { text: 'foo' }

The following examples use Atom/RSS2 format for illustration purpose only and do not necessarily conform to the W3C standard.

Text

Text value of an element

  • Input:

    <feed>foo</feed>
  • Template: { text: 'feed' }

  • Output: { text: 'foo' }

Text (second level)

Text value of an element located in second level

  • Input:

    <feed>
      <title>foo</title>
    </feed>
  • Template: { text: 'feed/title' }

  • Output: { text: 'foo' }

Text (all level)

If the element is located in very deep level, instead of using locate/very/deep/level, you can use double-slash prefix. This only works if the element name is unique.

  • Input:

    <rss>
      <channel>
        <title>foo</title>
      </channel>
    </rss>
  • Template: { text: '//title' }

  • Output: { text: 'foo' }

Text (distinct elements)

  • Input:

    <feed>
      <title>foo</title>
      <updated>2020</updated>
    </feed>
  • Template: { title: 'feed/title', updated: 'feed/updated' }

  • Output: { title: 'foo', updated: '2020' }

Attribute

Parse value of an attribute

  • Input:

    <feed>
      <link href="example.com"/>
    </feed>
  • Template: { feedLnk: 'feed/link/@href' }

  • Output: { feedLnk: 'example.com' }

Text (multiple elements)

Parse all entries of a specified element

  • Input:

    <feed>
      <entry>
        <title>first</title>
      </entry>
      <entry>
        <title>second</title>
      </entry>
    </feed>
  • Template:

    { items: [ 'feed/entry', { title: 'title' } ] }
  • Output:

    {
      "items": [
        {
          "title": "first"
        },
        {
          "title": "second"
        }
      ]
    }

Text (similar elements, similar sub-entries)

Parse all sub-entries of a specified element

  • Input:

    <feed>
      <entry>
        <title>title A</title>
        <category>apple</category>
        <category>orange</category>
      </entry>
      <entry>
        <title>title B</title>
        <category>peach</category>
        <category>mango</category>
      </entry>
    </feed>
  • Template:

    {
      items: [
        'feed/entry',
        {
          title: 'title',
          category: [
            'category',
            '.'
          ]
        }
      ]
    }
  • Output:

    {
      "items": [
        {
          "title": "title A",
          "category": [
            "apple",
            "orange"
          ]
        },
        {
          "title": "title B",
          "category": [
            "peach",
            "mango"
          ]
        }
      ]
    }

Attribute (multiple elements, multiple sub-entries)

Parse all sub-entries of a specified element

  • Input:

    <feed>
      <entry>
        <title>title A</title>
        <category term="apple"/>
        <category term="orange"/>
      </entry>
      <entry>
        <title>title B</title>
        <category term="peach"/>
        <category term="mango"/>
      </entry>
    </feed>
  • Template:

    {
      items: [
        'feed/entry',
        {
          title: 'title',
          category: [
            'category',
            '@term'
          ]
        }
      ]
    }
  • Output:

    {
      "items": [
        {
          "title": "title A",
          "category": [
            "apple",
            "orange"
          ]
        },
        {
          "title": "title B",
          "category": [
            "peach",
            "mango"
          ]
        }
      ]
    }