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== JSON Documents: Basics==

What is a JSON?
* A JSON itself is a JSON object, marked by [https://json-schema.org/understanding-json-schema/basics.html#hello-world]

<syntaxhighlight lang="json">
{}
</syntaxhighlight>

==JSON Documents: Key-Value-Pairs==

*A JSON object defines key(word):value pairs.
*Keys are formatted as strings, marked by quotation marks ("").

<syntaxhighlight lang="json">
{
    "key": "value"
}
</syntaxhighlight>

==JSON Documents: Data types==

*The key is always a string
*The value can be a string, a number, a boolean or null
*Additional data types are only possible by referencing them as external resources

<syntaxhighlight lang="json">
{
    "key": "value",
    "string": "any string value",
    "number": 1.0,
    "bool": true,
    "empty": null,
    "image": "https://my.cloud/image-1.png"
}
</syntaxhighlight>

==JSON Documents: Subobjects==

*The value can also be a JSON document (object) itself
*A nested object can have the same key-value pairs as the root document
*There is no limit in the nesting depth

<syntaxhighlight lang="json">
{
    "key": "value",
    "string": "any string value",
    "number": 1.0,
    "bool": true,
    "empty": null,
    "object": {
        "has": "it's own key-value-pairs"
    }
}
</syntaxhighlight>

==JSON Documents: Arrays==

*The value can also be an array (list)
*An array can contain any element, including objects and nested arrays

<syntaxhighlight lang="json">
{
    "key": "value",
    "string": "any string value",
    "number": 1.0,
    "bool": true,
    "empty": null,
    "object": {
        "has": "it's own key-value-pairs"
    },
    "array": [
        "a list", 
        {"of": "any"}, 
        ["item1", 1.0, true]
    ]
}
</syntaxhighlight>

==JSON Documents: Pointer (1)==

Pointer allow reference to
*An object within the JSON document

<syntaxhighlight lang="json">
{
    "firstname": "Susan",
    "surname": "Birch",
    "kids": ["Anne", "Tom"],
    "emergency_contact": {
        "$ref": "#/kids/0"
    }    
}
</syntaxhighlight>
Syntax [https://www.rfc-editor.org/rfc/rfc6901]:

<nowiki>#</nowiki>        - the whole document = self-reference

<nowiki>#</nowiki>/kids   - the value of the key "kids"

<nowiki>#</nowiki>/kids/0 - the first item within the array "kids"
==JSON Documents: Pointer (2)==
Pointer allow reference to
*An object within the JSON document
*An external JSON document

<syntaxhighlight lang="json">
{
    "firstname": "Susan",
    "surname": "Birch",
    "partner": {
        "$ref": "http://www.personaldata.com/walter.birch.json"
    }
}
</syntaxhighlight>

==JSON Documents: Next==

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