Json training

1. JavaScript Object Notation
JSON
Ela

2. What is JSON?
2
• JSON stands for JavaScript Object Notation
• JSON is a lightweight, text-based, data-interchange format
• JSON is "self-describing" and easy for humans to read and write.
• JSON is a text format that is completely language independent but uses conventions
that are familiar to programmers. It is easy for machines to parse and generate.
• JSON defines a small set of formatting rules for the portable representation of
structured data. The JSON format specifications was specified by Douglas Crockford
in the early 2000s.
• The file type for JSON files is .json and MIME type for JSON text is "application/json"

3. What JSON looks like?
3

4. History of JSON
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• 1999 ECMAScript Third Edition
• 2001 State Software, Inc.
• 2002 JSON.org
• 2005 Ajax
• 2006 RFC 4627

5. How is JSON Used:
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• Browser/server communication.
• Inter server communication.
• NoSQL database.
• Config files

6. JSON Syntax Rules
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JSON syntax is derived from JavaScript object notation syntax:
• Data is in name/value pairs
• Data is separated by commas
• Curly braces hold objects, a collection of name/value pairs
• Square brackets hold arrays, an ordered list of values

7. Object
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• An object is an unordered set of name/value pairs.
• An object begins with { (left brace) and ends with } (right brace).
• Each name is followed by : (colon) and the name/value pairs are separated
by , (comma).
Examples:
{
“firstName”: “Peter”,
“lastName”: “Gruenbaum”
}

8. Array
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• An array is an ordered collection of values.
• An array begins with [ (left bracket) and ends with ] (right bracket).
• Values are separated by , (comma) and can mix data types.
Examples:
• [4, 6, 23.1, -4, 0, 56]
• [“red”, “green”, “blue”]
• [65, “toast”, true, 21, null, 100]

9. Value
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• A value can be a string in double quotes, or a number, or true or false or null, or
an object or an array. These structures can be nested.

10. Value
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• Strings: sequence of zero or more Unicode characters, enclosed by double quotes,
using backslash escapes. A character is represented as a single character string.
• Numbers: integer or decimal, positive or negative
• Boolean: true or false, no quotation marks
• Null: means “nothing”, no quotation marks.
• Whitespace can be inserted between any pair of tokens

11. Nesting
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• Nesting involves putting arrays and objects inside each other.
• You can put arrays inside objects, objects inside arrays, arrays inside arrays, etc.

12. 12
Online JSON Editor
• https://jsoneditoronline.org/
Online JSON Validator
• https://jsonlint.com/
IDE (for local development)
• http://brackets.io/
Chrome plugins
• JSON Formatter
Tools

13. Hands On
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• Lab: Create a JSON object that introduces you. Feel free to add more fields like
hobbies, etc.

14. JSON Parse
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• A common use of JSON is to exchange data to/from a web server
• When receiving data from a web server, the data is always a string
• Parse the data with JSON.parse(), and the data becomes a JavaScript object
JSON Stringify
• A common use of JSON is to exchange data to/from a web server
• When sending data to a web server, the data has to be a string
• Convert a JavaScript object into a string with JSON.stringify()

15. References
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• https://json.org/
• https://www.ietf.org/rfc/rfc4627.txt
• http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf