In HTML, the formal structure of a webpage consists of nested elements. However, when it comes to mapping, specifically compact mappings, nesting is not allowed. A compact mapping is a way of writing key-value pairs in a simpler and more concise form.
The reason nesting is not allowed in compact mappings is because it would lead to ambiguity and make it difficult to determine the hierarchy and relationships between the elements.
Let’s take an example to illustrate this:
{
"name": "John Doe",
"age": 30,
"address": {
"street": "123 Main St",
"city": "New York"
}
}
In this example, the nested “address” object has key-value pairs for “street” and “city”. If we were to convert this to a compact mapping, it would look like:
{
"name": "John Doe",
"age": 30,
"address": { "street": "123 Main St", "city": "New York" }
}
As you can see, the nested “address” object is written within curly braces without any indentation or line breaks. This is a compact mapping.
If we were to nest the key-value pairs within the compact mapping, it would create ambiguity:
{
"name": "John Doe",
"age": 30,
"address": {
"street": "123 Main St",
"city": "New York"
}
}
In this case, it becomes unclear whether the nested key-value pairs belong to “address” or are separate key-value pairs at the same level as “address”.
To avoid this ambiguity and maintain the clarity of the data structure in mapping, nested mappings are not allowed in compact mappings.