Chapter 20

JSON

WHAT’S IN THIS CHAPTER?

  • Understanding JSON syntax
  • JSON parsing
  • JSON serialization

There was a time when XML was the de facto standard for transmitting structured data over the Internet. The first iteration of web services was largely XML-based, highlighting its target of server-to-server communication. XML was not, however, without its detractors. Some believed that the language was overly verbose and redundant. Several solutions arose to counter these problems, but the Web had already started moving in a new direction.

Douglas Crockford first specified JavaScript Object Notation (JSON) as IETF RFC 4627 in 2006 even though it was in use as early as 2001. JSON is a strict subset of JavaScript, making use of several patterns found in JavaScript to represent structured data. Crockford put forth JSON as a better alternative to XML for accessing structured data in JavaScript, since it could be passed directly to eval() and didn’t require the creation of a DOM.

The most important thing to understand about JSON is that it is a data format, not a programming language. JSON is not a part of JavaScript even though they share syntax. JSON is also not solely used by JavaScript, since it is a data format. There are parsers and serializers available in many programming languages.

SYNTAX

JSON syntax allows the representation of three types of values:

  • Simple Values — Strings, numbers, Booleans, and null can all be represented in JSON using the same syntax as JavaScript. The ...

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