Added lodash and merge option in mapAST

[chaosmaker]

Dear maintainers of react-i18next,

Below is my pull request for #1117 where I initially requested the option to have props within a <0 ...props></0> passed to its final component. It is a very simple fix.

I have tried running npm run test but it seems the distribution lacks dtslint/dtslint.json - I have tested the code extensively and don't see any issues that may occur.

I also wasn't sure where to change the documentation. If you point me in the right direction I will adapt where necessary.

Checklist

• only relevant code is changed (make a diff before you submit the PR)
• run tests npm run test
• tests are included
• documentation is changed or added

[coveralls]

Coverage increased (+0.04%) to 95.775% when pulling adb6b07 on chaosmaker:FR-prop-passing into 6001a31 on i18next:master.

[adrai]

Is full lodash dependency really needed?

Can't the same be achieved also with: const child = Object.keys(node.attrs).length !== 0 ? { props: node.attrs, ...tmp } : tmp; ?

[chaosmaker]

I tried that first and couldn't get it to work, the props are overwritten by {} that is in tmp. _.merge has the advantage that it will deep merge the properties, so if there are defined properties like class etc, they will be merged together as opposed to replaced. To reduce full lodash I have changed it to load lodash.merge only.

[jamuhl]

sadly won't accept any lodash dependency...this adds over 3.7kb gzipped: https://bundlephobia.com/result?p=lodash.merge@4.6.2

also please add some test cases for future regression:

• asserting feature works
• not overwrites props set in code (props already on the node)

thank you 👍

[chaosmaker]

Ok I have removed lodash and just focused on merging the props using a small function. So nice and light. The code is set in such a way that original values in <Trans><anything ...prop></Trans> are not overwritten when set in the language file. Only missing props are added.

Also not sure why coverage decreased? I didn't remove anything?

I am a bit new to github/code reviews - how/where do I add some test cases?

also please add some test cases for future regression:

• asserting feature works
• not overwrites props set in code (props already on the node)

[jamuhl]

test can be added here: https://github.com/i18next/react-i18next/blob/master/test/trans.render.spec.js

coverage decreased as your newly added code is not covered.

[chaosmaker]

I added some tests which seem to work. Hope that is all you need!

[jamuhl]

looks ok...will check this in detail tomorrow (merge & publish)

[adrai]

Thanks, it's included in v11.5.0