kafkahw/jest-func-module-mock.md

## jest-func-module-mock.md

      
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              jest-func-module-mock.md
            
          
Good SO post: https://stackoverflow.com/questions/53174202/how-to-mock-a-function-in-jest


Good Medium post: https://medium.com/@qjli/how-to-mock-specific-module-function-in-jest-715e39a391f4


Good discussion here: jestjs/jest#936 (comment)


Personal experience


import the module as a whole. for instance, import * as Blah from '../blah';


const mock = jest.spyOn(Blah, '<mocked_function_name>');


mock.mockImplementationOnce( () => {});