react-native build error on import

I reproduced this from a new npx react-native init reproProj. Note that android studio, sdk and emulator are prerequisite to the init command and then launching reproProj with npm run android.

I’m not too familiar with the build environment for react-native but anyhow taking the following steps with reproProj

1. npm i -S --no-optional sanctuary
2. add import * as S from 'sanctuary' to the generated App.js
3. npm run android

I get:

    at ModuleResolver.resolveDependency (D:\src\reproProj\node_modules\metro\src\node-haste\DependencyGraph\ModuleResolution.js:186:15)
    at ResolutionRequest.resolveDependency (D:\src\reproProj\node_modules\metro\src\node-haste\DependencyGraph\ResolutionRequest.js:52:18)
    at DependencyGraph.resolveDependency (D:\src\reproProj\node_modules\metro\src\node-haste\DependencyGraph.js:287:16)
    at Object.resolve (D:\src\reproProj\node_modules\metro\src\lib\transformHelpers.js:267:42)
    at D:\src\reproProj\node_modules\metro\src\DeltaBundler\traverseDependencies.js:434:31
    at Array.map (<anonymous>)
    at resolveDependencies (D:\src\reproProj\node_modules\metro\src\DeltaBundler\traverseDependencies.js:431:18)
    at D:\src\reproProj\node_modules\metro\src\DeltaBundler\traverseDependencies.js:275:33
    at Generator.next (<anonymous>)
    at asyncGeneratorStep (D:\src\reproProj\node_modules\metro\src\DeltaBundler\traverseDependencies.js:87:24)
[Wed Oct 07 2020 19:04:00.925]  BUNDLE  ./index.js

error: Error: Unable to resolve module `util` from `node_modules\sanctuary-def\index.js`: util could not be found within the project.

The above workflow works fine for other npm libs such as ramda or redux.

npx react-native --version is 4.13.0 metro: 0.58.0, metro-core at 0.58.0, sanctuary at 3.1.0 sanctuary-def at 0.22.0

I’m not familiar with the usage of require where util is set up but I gather that it is not specifying that a js file be resolved. Perhaps “metro node-haste” misinterprets the require usage in a similar way.

Edit - I tried updating metro to their latest release 0.63.0 but that seems to have broken something in the otherwise as generated app/build.

[llaenowyd]

Not at this time! Thanks for your contributions to the development of functional techniques in Javascript!

[davidchambers]

It’s not clear to me whether there is something I could change to make Sanctuary work better for you, @llaenowyd. Let me know if there is. 😃