• Origins:
  • A subset of the JavaScript/ECMAScript programming language for defining objects literals
• What is JSON Now?
  • A language-independent way of marking up hierarchical data (a.k.a., a data interchange format)

• Values:
  • Numbers
  • Strings (must be within double quotes)
  • false/true
  • null
• Name-Value Pairs:
  • name:value
• Objects:
  • { nvp [,nvp...] }
• Arrays:
  • [ element [,element...] ]

• An Issue:
  • How can we distinguish a JSON file from a JavaScript/ECMAScript file?
• The Solution:
  • Use the MIME type application/json

A Single Object

jsonexamples/basics/person.json

{
    "firstName": "John",
    "lastName": "Doe",
    "age": 53,
    "address": {
        "streetAddress": "879 Paul St.",
        "city": "Harrisonburg",
        "state": "VA",
        "postalCode": 22801
    },
    "phoneNumbers": [
        "540-434-5555",
        "540-568-4411",
        "540-555-1234" 
    ] 
}
        

An Array of Objects

jsonexamples/basics/incidents.json

{
  "date": "1 Jan 2001",
  "breakdowns": [
    {
      "description": "Minivan ran out of gas on I81"
    },
    {
      "description": "Minivan with engine trouble on Rt. 42"
    },
    {
      "description": "Minivan with flat tire on Main St."
    }
  ],
  "accidentReports": [
    {
      "size": 1,
      "type": "Overturned poultry truck on Port Rd."
    },
    {
      "size": 2,
      "type": "Head-on crash on I81 at Exit 245"
    }
  ]
}