Javascript json helper how to#

The JsonCpp implementation defines Json::Reader and Json::Writer, specifying the interfaces to JSON readers and writers, respectively. We explicitly reference the std namespace for brevity, although don't do so for the Json namespace, in which JsonCpp defines all of its interfaces. This example begins by including the necessary includes, including json/json.h, which defines the interface to JsonCpp. Its plaintext nature makes it amenable to compression over the wire using popular compression schemes such as gzip (available inside most web servers and web clients), and its format is easier for humans to read than the more verbose XML. The self-documenting nature of JSON makes it an ideal choice for data transport as you develop new objects, despite its lack of support for comments as you might find in XML.

This includes primitive values (self-documenting because each value is accompanied by an attribute), flat objects with simple values including maps, and arrays of simple or complex objects.

Javascript json helper how to#

You can represent a lot of common objects using JSON, including most objects that don't have a lot of binary data (For ideas on how to represent binary data using JavaScript and JSON, see Chapter 8, Using JSON for Binary Data Transfer). The attribute-name-attribute-value property of JSON, along with the ability to nest values and represent arrays, gives JSON a lot of flexibility. There's no need to have each pair on its own line, for example, and the indentation is completely arbitrary. Note that many other kinds of values, such as date/time pairs or individual characters are not supported by JSON.Īlthough it's not entirely clear from this example, whitespace is insignificant. Whole objects consisting of more attributes and values, such as the two-array values in the entries valueĪlternatively (although this example doesn't show it), the Boolean values true and false Numbers (either integers or floating point) such as 2 or 37.17667Īrrays (comma-delimited values contained in square brackets), such as the value for entries Let's take a look at some JSON returned by the web API, available at, and modified a bit by me to make the example clear (later, in Chapter 4, Using JSON in AJAX Applications with jQuery and AngularJS, you'll learn how to fetch this data yourself using a web browser and JavaScript):Ĭharacter strings (enclosed in double quotes) such as KF6GPE We'll look more at server-side languages in Chapter 2, Reading and Writing JSON on the Server. These languages are often used for client-side development, which is what we will focus on here. In this first chapter, you will learn how to work with JSON in languages specified at the beginning of this chapter.

JSON provides an ideal means to encapsulate data between the client and server. Originally derived from the JavaScript syntax (hence its name) for use in web applications as an alternative to the more verbose and structured Extensible Markup Language ( XML), it is now used for data serialization and transport in many standalone and web applications. It's an open standard to represent data as attributes with values. JSON stands for JavaScript Object Notation.