JSON is a format for storing and transmitting data that originates from the way objects are written in JavaScript, but is characterized by its universality and compatibility with other programming languages. Its readable and lightweight syntax makes JSON primarily used in web and mobile applications, because it promotes their fast, efficient operation.
What is JSON?
JSON (Java Script Object Notation) is a lightweight text format that makes it easier and faster to exchange data, for example, between a server and a website. The JSON syntax is supported by various programming languages, and its relationship with JavaScript concerns only the similar way of writing objects. The first main goal of JSON was to simplify communication between the frontend and the backend.
JSON was described by Douglas Crockford in 2001 (although it had been used since the 1990s) and standardized in the ECMA–404 specification in 2013. The second edition of the ECMA-404 standard was released in December 2017. Other documents with specifications defining the correct JSON syntax are the RFC 4627 collection and the ISO/IEC 21778:2017 standard.
What are the main features of the JSON format?
The flexible JSON format is distinguished by its easy interpretation of data. Its readable syntax is easier for users to understand compared to XML or CSV formats. Moreover, it promotes fast data exchange and higher efficiency of digital services, making it primarily used in building web and mobile applications.
How does JSON work?
What data types does JSON support?
The data types supported by JSON are:
- string (text string) – character strings enclosed in double (not single!) quotes, where special characters in the string, including quotes, must be preceded by a backslash (/) character,
- number (number) – are not enclosed in quotes unless they are to constitute a character string. Importantly, fractional numbers require a period, not a comma,
- boolean (logical value) – corresponds to true or false. Like numbers, they are not enclosed in quotes,
- null (empty literal) – indicates that the value has not been set. It is also not enclosed in quotes,
- array (array) – contains various types of values in square brackets. Arrays can contain objects and other arrays,
- object (object) – is a complex structure with values and keys assigned to them in the form of character strings. Value and key are a pair separated by a colon. Almost every pair (except the last one in an object) is followed by a comma. Objects, unlike arrays, are distinguished by curly braces. Note – values in an object can be repeated, but keys must be unique.
Strings, numbers, booleans, and empty literals are simple types, while arrays and objects are composite types.
Furthermore, JSON allows the use of nested object structures, such as placing arrays and objects within arrays, which can be used to store and send hierarchical, complex data.
How does JSON facilitate data exchange between servers and web applications?
JSON simplifies the transfer of data between different technologies, including between web and mobile applications and servers written in other programming languages. Transferring information in the lightweight JSON format allows for maintaining dynamic, interactive web environments that foster positive customer experiences. Moreover, using JSON speeds up some processes in the team, which even makes project management easier.
JSON and other data formats
What is the difference between JSON and XML?
XML (Extensible Markup Language), called an extensible markup language, is as universal as JSON, but it is used to design more complex hierarchical structures. Data saved in JSON is more readable and easier to process. In addition, XML files that contain more characters are larger and carry the risk of slower data loading. If we save identical information in JSON and XML, it turns out that the first format contains much fewer characters that are not the target data. This makes JSON files generate much less load compared to XML and load faster.
Is JSON an alternative to CSV?
While JSON and CSV are text formats for storing data, there are significant differences between them. CSV (Comma-Separated Values) does not allow data to be saved in a hierarchical structure, unlike JSON, because it contains comma-separated values, which is an alternative to information stored in columns. Additionally, CSV does not use data types, is more difficult to scale and integrate with APIs.
Programming with JSON
What programming languages support JSON libraries?
JSON is supported by many programming languages, including C, C++, Java, JavaScript, PHP, Python, and Ruby.
How do JSON.parse() and JSON.stringify() work?
The JSON.parse() function allows you to convert text data into a JavaScript object. In turn, the JSON.stringify() function allows you to change a JavaScript object into a text string.
What tools can be used to validate JSON?
A developer does not need to have their own JSON validation tool. They can simply use external online validators that quickly verify syntax correctness, such as JSON Schema Validator, JSONLint Validator and Formatter, or JSON Formatter & Validator.
JSON Use
How does JSON improve the performance of progressive applications?
By using JSON in a progressive application, you can reduce the risk of delayed data transfer, especially when the user uses slow internet. A weak Wi-Fi signal, e.g. in a public space, affects the application loading speed. The lightweight JSON format helps maintain a satisfactory fluidity and speed of operation of a PWA (Progressive Web App) despite unfavorable external conditions. What’s more, progressive applications are based on the manifest.json file, which allows, among other things, using a PWA page without having to download an application from Google Play or the App Store.
How does JSON support the management of data configurations and settings?
The JSON format is used not only for efficient data transfer, but also for storing and managing configuration files of mobile and web applications, which makes them easier to modify by the IT department.
JSON and the future of technology
How has JSON influenced the development of NoSQL and databases?
The growing popularity of JSON has contributed to the development of NoSQL databases, which are characterized by easy scalability, greater flexibility, and higher performance compared to SQL databases. Some of the most popular NoSQL databases are Redis, MongoDB, and Couchbase (formerly Membase).
