What is Jest in React?

Jest is a JavaScript(JS)-based framework for testing React, and React Native and other JavaScript(JS)-based web applications. In many cases, unit tests do not provide accurate results when run on the frontend of any software. Jest it will be reduces this issue by allowing you to write faster, more effective front-end tests.

Note: Now You can also run your Jest test scripts on LambdaTest cloud.

In addition, Jest can be used to validate almost anything around JavaScript(JS), especially the browser rendering of web applications. With its intuitive API(Application programming interface) and easy setup and installation, Jest has become one of the most popular JavaScript(JS) testing frameworks available today.

With a built-in mockery library, an assertion library, and a test runner, Jest acts as a full-stack testing framework that allows you to write tests for JavaScript(JS) Library Projects such as AngularJS, Vue JS, Node JS, Babel, and TS(TypeScript).

The Rise of Jest Framework

Initially created by Facebook(FB), Jest is a popular testing framework for React web applications. Since then, the tool has grown in popularity and is used for testing both front-end and back-end web applications.

Facebook(FB), Airbnb, Spotify, The New York Times, Travel Perk, Twitter, and Instagram are among the prominent companies that reportedly adopt Jest in their tech stack.

Check out The State of JS 2021 Jest testing data on the basis of web developer Satisfaction, Interest, Usage and Awareness.

Satisfaction:

According to the State of javascript(JS )survey, Jest has been the most interesting and satisfying framework for JavaScript(JS) testing. There has been a constant rise in the level of satisfaction among the tester community ( 59% in 2016 to 93% in 2021).

Interest:

The interest among the web developers and testers community has also shown a consistent rise, i.e., from 59% in 2016 to 79% in 2021.

Usage:

According to the State of JS(javascript) survey, Jest has been the most widely used testing framework for JavaScript(JS) testing, among other frameworks. It was showing the significant rise from 8% in 2016 to 73% in 2021.

Awareness:

Since 2016, Jest has showing a consistent rise in its awareness among the tester community. Not only this, prominent companies like Facebook(FB), Spotify, Airbnb, Twitter, etc, have also adopted Jest in their tech stack. It has showing a significant rise from 36% in 2016 to 95% in 2021.

The State of JS(Javascript) survey also shows that 57 % of testers and web developers would like to use it again for their testing needs, and around 15% would like to learn Jest.

Features of Jest

There are more automated frameworks that are provided for cross-browser testing. But Jest is better than the rest. Here is why:

• Jest is faster than different frameworks when it comes to executing test cases. In addition to speeding up the entire test suite, Jest offers great efficiency in its watch mode enabling users to analyze how particular changes affect the overall output.
• Jest framework offers pre-commit hooks, which are an effective method or function to reduce the number of tests performed by a test suite. These tests are very popularly known as snapshot to tests and are useful in reducing regression testing efforts.
• Jest comes with all of the all features that are required in a modern testing framework. Built-in modules provide very good support for all plugins, and there is no need to download any other third-party executable, like Mocha or Cucumber, to perform certain activities. In case you want to add any other library(packages) with Jest, they are easily configurable and there are no compatibility issues.
• Migrating a present test project to the Jest framework is easy and can be completed programmatically using code mods module.
• The framework is not just a normal test runner; on the other hand, it also offers most features such as auto mocking modules, coverage thresholds, and mappers. This includes supported for different projects in the same runner and customer resolvers such as Babel and Webpack.
• According to the StateofJS(javascript) survey, here are some other reasons why web developers prefer Jest over other frameworks.