jest/no-deprecated-functions Style
What it does
Over the years Jest has accrued some debt in the form of functions that have either been renamed for clarity, or replaced with more powerful APIs.
This rule can also autofix a number of these deprecations for you.
jest.resetModuleRegistry
This function was renamed to resetModules in Jest 15 and removed in Jest 27.
jest.addMatchers
This function was replaced with expect.extend in Jest 17 and removed in Jest 27.
require.requireActual & require.requireMock
These functions were replaced in Jest 21 and removed in Jest 26.
Originally, the requireActual & requireMock the requireActual& requireMock functions were placed onto the require function.
These functions were later moved onto the jest object in order to be easier for type checkers to handle, and their use via require deprecated. Finally, the release of Jest 26 saw them removed from the require function altogether.
jest.runTimersToTime
This function was renamed to advanceTimersByTime in Jest 22 and removed in Jest 27.
jest.genMockFromModule
This function was renamed to createMockFromModule in Jest 26, and is scheduled for removal in Jest 30.
Why is this bad?
While typically these deprecated functions are kept in the codebase for a number of majors, eventually they are removed completely.
Example
jest.resetModuleRegistry; // since Jest 15
jest.addMatchers; // since Jest 17