protractor

Protractor may refer to two different tools or devices, depending on the context.

Protractor (instrument) is a measuring device used to determine angles. It typically consists of a flat or circular plate marked with degree scales, a pivot, and a rule or arm. Semicircular protractors are common in education, while full-circle versions are used in engineering and drafting. To measure an angle, one leg is aligned with one side of the angle and the other leg with the other side, and the reading on the degree scale indicates the measure. Materials range from plastic to metal or glass, and tolerances vary by design and application.

Protractor (testing framework) was a JavaScript-based end-to-end testing framework for Angular and AngularJS applications. It was built on top of Selenium WebDriver and runs tests in real browsers. Protractor simplifies automating user interactions and handles synchronization with Angular, so tests wait for asynchronous tasks to finish. It uses a configuration file to declare test suites and can be paired with Jasmine, Mocha, or Cucumber. It can test non-Angular apps using a flag. In the early 2020s, development of Protractor was discontinued, and the Angular team recommended alternatives such as Playwright, Cypress, or plain Selenium WebDriver for non-Angular apps. Despite deprecation, some projects continued to use it during a transition period.