Make logging customizable

[sapegin]

Right now Styleguidist uses console.log to show some potentially useful messages like:

No webpack config found. You may need to specify "webpackConfig" option in your style guide config:
https://github.com/styleguidist/react-styleguidist/blob/master/docs/Webpack.md

We should do it only when Styleguidist is started from CLI, not from the API (or tests). Would be nice to be able to customize the logging somehow — I don’t really know what would be the right approach — maybe pass a logging function everywhere or something like that.

[sapegin]

This look very close: https://github.com/js-cli/glogg

[adityavohra7]

Not having react-styleguidist output anything when its tests run definitely makes sense, but I wonder if there are situations wherein people may want the API to output stuff similar to what the CLI does?

Say I wanted to abstract away or package up my JS infra (build + configs), sort of like what create-react-app does, and provide the consumers of this JS infra package an npm run script like start-workbench, which under the hood uses the react-styleguidist API.

Having this run script output warnings or compilation errors would definitely be useful, and would only be possible if the API had output (I think?). Though at the same time this start-workbench script could just shell out to the react-styleguidist CLI, or it could re-implement some of the output forwarding of the CLI implemented here. So I'm not sure 😅

[sapegin]

@adityavohra7 That’s exactly what I want to do! I just not sure about the API and implementation.

Probably pass a logger object to the API like this:

const styleguide = styleguidist({
  components: './lib/components/**/*.js',
  logger: {
    error: msg => console.error(msg)
  }
});

[sapegin]

There’s a PR: #510.