Allows preserving children from whitelistPatterns

[cmizzi]

Proposed changes

Related to #39

Types of changes

• Add ability to provide a whitelistPatterns object instead of RegExp in order to resolve a keepChildren option to preserve left to right reader

Checklist

• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• Assert Flow is working as well
• I have added necessary documentation (if appropriate)

[Ffloriel]

Thanks for the PR.
I think it's important to discuss about the API itself.
From the PR, if I understand correctly, someone would whitelist patterns the following way:

whitelistPatterns: [
                {
                    pattern: /^double-class$/,
                    keepChildren: true
                }
            ]

I think it would be better to have a different property for whitelist patterns.
The list of patterns can be long depending on the use cases and it could be easier to configure with a different property:

whitelistPatterns: [
                {
                    pattern: /^single-class$/,
                    keepChildren: true
                },
                {
                    pattern: /^double-class$/,
                    keepChildren: true
                },
                {
                    pattern: /^triple-class$/,
                    keepChildren: false
                },
                {
                    pattern: /^quadruple-class$/,
                    keepChildren: false
                },
                {
                    pattern: /^quintuple-class$/,
                    keepChildren: true
                },
            
            ]

vs

whitelistPatterns: [/^triple-class$/, /^quadruple-class$/],
whitelistPatternsChildren: [/^single-class$/, /^double-class$/, /^quintuple-class$/]

@cmizzi @jsnanigans, what do you think about this? I'm not sure whitelistPatternsChildren is the best name for it but we can come up with something better.

[cmizzi]

Great idea. But, what happen if both contain same value ? We need a priority manager. First, we should manage whitelistPatternsChildren if fails, tests with whitelistPatterns

[Ffloriel]

In my opinion, the priority should go to the most conservative option. WhitelistPattersChildren will conserve children selectors. If case of a misconfiguration, giving priority to this option will not remove wanted css and break the application style.
So if both contain the same value, WhitelistPattersChildren will have the priority.

[cmizzi]

I've applied changes. Now, a whitelistPatternsChildren is defined and works as excepted

[Ffloriel]

LGTM

[Ffloriel]

Thanks for the PR. The option is now available with v0.21.0

[robertvrabel]

Thank you for this PR! Looking forward to trying it out :)