When use istanbul, is there any way to dynamic require config.js?

Question

The logEnable is write in config.js, is there any way to change the value during testing? So than I can improve the branch coverage.

Answer 1

You could ignore parts of code from testing: https://github.com/gotwarlost/istanbul/blob/master/ignoring-code-for-coverage.md

Skip an if or else path with /* istanbul ignore if */ or /* istanbul ignore else */ respectively.

For all other cases, skip the next 'thing' in the source with: /* istanbul ignore next */

Or add a single test that checks just those logging functions with both logging enabled and disabled (you can override required modules, like your config, for example with proxyquire: https://github.com/thlorenz/proxyquire).