JSON Arrays to XML Repeated Elements

Arrays are the most challenging part of JSON-to-XML conversion because XML has no native array type. Instead, arrays are represented by repeating sibling elements with the same tag name.

A JSON array of primitives:

{
  "colors": ["red", "green", "blue"]
}

Common XML representations:

Option 1: Wrapper + repeated element

<colors>
  <color>red</color>
  <color>green</color>
  <color>blue</color>
</colors>

Option 2: Repeated element only (no wrapper)

<color>red</color>
<color>green</color>
<color>blue</color>

Arrays of objects:

{
  "users": [
    { "name": "Alice", "role": "admin" },
    { "name": "Bob", "role": "editor" }
  ]
}

<users>
  <user>
    <name>Alice</name>
    <role>admin</role>
  </user>
  <user>
    <name>Bob</name>
    <role>editor</role>
  </user>
</users>

Naming conventions for array items:

Most converters derive the singular form of the item element name from the plural wrapper:

• users -> user
• items -> item
• entries -> entry

Some converters use a generic <item> tag or let you configure the child element name.

Nested arrays (arrays within arrays):

{ "matrix": [[1, 2], [3, 4]] }

This is particularly tricky in XML. One approach:

<matrix>
  <row>
    <item>1</item>
    <item>2</item>
  </row>
  <row>
    <item>3</item>
    <item>4</item>
  </row>
</matrix>

The reverse problem (XML to JSON) is equally challenging: when you see repeated sibling elements, should they become a JSON array? Most converters use a heuristic: if two or more siblings share the same tag name, they become an array. A single element becomes an object. This inconsistency is a common source of bugs.