Add a stripExtensions option for RN support

[MatthieuLemoine]

See #90 for context.

Example :

#before.babelrc
{
  "presets": ["react-native"],
  "plugins": [
    [
      "module-resolver",
      {
        "root": ["./src"],
        "extensions": [".js", ".ios.js", ".android.js"]
      }
    ]
  ]
}

#after.babelrc
{
  "presets": ["react-native"],
  "plugins": [
    [
      "module-resolver",
      {
        "root": ["./src"],
        "extensions": [".js", ".ios.js", ".android.js"],
        "stripExtensions": [".ios.js", ".android.js"]
      }
    ]
  ]
}

/*
- module
  - index.ios.js
  - index.android.js
*/
// Before 
import module from 'module'; // -> import module from './module/index.ios';
// After
import module from 'module'; // -> import module from './module';

We let the RN packager to choose which file to import depending on the platform.

[codecov]

Codecov Report

Merging #205 into master will not change coverage.
The diff coverage is 100%.

Impacted Files	Coverage Δ
src/resolvePath.js	100% <ø> (ø)	⬆️
src/utils.js	100% <100%> (ø)	⬆️

[chirag04]

i don't understand how this module works but y is : import module from 'module'; // -> import module from './module'; not the default behavior. y not always strip?

[MatthieuLemoine]

Actually you can think of it as this following list of steps :

• convert to relative path : module -> ./module/index.ios.js
• remove extension (using path.extname) : ./module/index.ios.js -> ./module/index.ios
• remove index from path : ./module/index.ios -> ./module/index.ios (do nothing here because the filename is not index but index.ios)

With this PR :

• convert to relative path : module -> ./module/index.ios.js
• remove extension (using stripExtensions) : ./module/index.ios.js -> ./module/index
• remove index from path : ./module/index -> ./module

[chirag04]

@MatthieuLemoine thanks for the explanation, yeah makes it easy.

so i guess what i'm saying is at this step: remove extension (using path.extname) : ./module/index.ios.js -> ./module/index.ios
is user is providing a list of extensions then iterate through those extensions are remove them.

So the steps look like:

• convert to relative path : module -> ./module/index.ios.js
• remove extension (using extensions array or path.extname) : ./module/index.ios.js -> ./module/index
• remove index from path : ./module/index -> ./module

Notice the change on step 2. we loop through extensions array and remove every possible extension. since ios.js is an extension we remove it from index.ios.js

[MatthieuLemoine]

Yeah we could do that but it will be a breaking change.
@tleunen seemed to not want this : #90 (comment)

But at the same time, if the user sets a custom extension, the extension should be printed in the resulted path, in order for NodeJS or any other tooling system to pick it without issue.

That's why I chose to add an option so that it will be transparent for all the users that don't need this.

[chirag04]

ah i see. that makes sense. i guess a stripExtensions: boolean could also work? not sure if there is a case where you want to strip some extensions and leave the rest.

[MatthieuLemoine]

Yes I thought about that. It's more about flexibility. For now I encountered this issue only with React Native where the extensions we want to strip are the same that those we want to support. I don't know about all the use cases.

But I'm willing to change the option name/type/value.

[tleunen]

Thank you for the contribution @MatthieuLemoine.
After reading the description, I now understand better the problem. I wonder though if, instead of adding a new option, we should strip the extensions by default.

When it's .js, you don't want it since it's extra information not required. But if you specify the plugin to also work with .android.js and ios.js, these things actually become "extensions", so they should be stripped too.

What do you think?

cc @fatfisz

[chirag04]

@tleunen that's what i was getting at here: #205 (comment). always strip would be awesome if it's not a blocker.

[fatfisz]

One backtick is enough - also a space is missing before "and" ;)

[fatfisz]

I need to get into the details, but this looks good!

Just one thought I already have - if we're putting the same extensions in two places, maybe something like "extensions": [".js", "~.ios.js", "~.android.js"] could work instead?

[MatthieuLemoine]

Well personally I'm fine with stripping the extension by default.

I can remove the option if you want @tleunen @fatfisz.

[tleunen]

I believe it's safe to strip it by default. I mean, to me it looks like it's a bug we're not doing that now.
What do you think @fatfisz?

[MatthieuLemoine]

I've updated the PR to strip by default. All tests are still passing.

[tleunen]

Thanks @MatthieuLemoine, I'll check the branch in one of my project tonight to make sure everything still work as before for a basic project, and I'll merge and release a new beta after if all is green :)

With this update, I believe we're really close to release the final version.