Add "type": "module" to package.json and rename CommonJS modules to .cjs

[benjamn]

https://nodejs.org/api/packages.html#packages_determining_module_system

[SimenB]

Hiya! Big fan of this change, but it makes Metro (aka React Native) unhappy. See facebook/metro#535. Ideally FB would fix this in Metro, but since they haven't bothered to respond in the issue it doesn't seem like it's a about to happen...

[SimenB]

I was able to work around it with this (stripped down from our larger one using Expo, so copy with caution) metro config:

const { getDefaultConfig } = require('metro-config');

const { resolver: defaultResolver } = getDefaultConfig.getDefaultValues();

const configuration = {
  resolver: { sourceExts: [...defaultResolver.sourceExts, 'cjs'] },
};

module.exports = configuration;