Set Jest's testEnvironment to "node" when not targetting a browser

[edmorley]

Currently the @neutrinojs/jest preset doesn't define testEnvironment, so Jest uses the default of 'jsdom':
https://jestjs.io/docs/en/configuration.html#testenvironment-string

This seems fine for projects that are targetting the browser (eg @neutrinojs/web, ...), however for @neutrinojs/node or @neutrinojs/library (with target: 'node') a more suitable value for testEnvironment would be 'node'.

I'm not sure of the best way of checking within @neutrinojs/jest when to override the environment - hardcoding presets is a non-starter, so perhaps by inspecting the babel preset-env compile targets?

[eliperelman]

What about getting the value of neutrino.config.target()? For example:

testEnvironment: neutrino.config.get('target') === 'node' ? 'node' : 'jsdom'

[edmorley]

Oh right yeah I forgot about the top level webpack target property. That will work well.