feat: add hook build:config

[clarkdo]

Types of changes

• Bug fix (a non-breaking change which fixes an issue)
• New feature (a non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Description

I didn't add any param for now since we already have extend for customising webpack config and this hook should avoid introducing more side effects.

Checklist:

• My change requires a change to the documentation.
• I have updated the documentation accordingly. (PR: #)
• I have added tests to cover my changes (if not applicable, please state why)
• All new and existing tests are passing.

[codecov-io]

Codecov Report

Merging #6349 into dev will decrease coverage by 0.03%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##              dev    #6349      +/-   ##
==========================================
- Coverage   95.71%   95.68%   -0.04%     
==========================================
  Files          79       79              
  Lines        2662     2665       +3     
  Branches      685      686       +1     
==========================================
+ Hits         2548     2550       +2     
- Misses         98       99       +1     
  Partials       16       16

Flag	Coverage Δ
#e2e	100% <ø> (ø)	⬆️
#fixtures	50.69% <66.66%> (+0.01%)	⬆️
#unit	92.34% <66.66%> (-0.03%)	⬇️

Impacted Files	Coverage Δ
packages/webpack/src/builder.js	92% <66.66%> (-0.79%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f1edd82...22f0377. Read the comment docs.

[manniL]

I'm wondering whether we should be more explicit (e.g. webpackConfig) and use the new patter (builder:)?

Also, we need docs (as usual) explaining the difference between the different methods of adding stuff to the webpack config (e.g. via extends).

[pimlie]

Why the [].concat? If the array contains objects then after the concat its still an array to the same references right?

[clarkdo]

The concat here is for supporting return value either array or object as single or multiple builds

[pimlie]

Thanks, actually I didnt know you could return values with callHook. Maybe I am just overseeing something simple but there is no return statement or whatever, so how does it even return a value?

[clarkdo]

Yes, that's true, it has been changed for a while, I've changed in new pr

[clarkdo]

@manniL Sorry, I don’t know the new hook pattern decision, is the new pattern corresponding to package? So maybe use hook name as ‘webpack:config’ ?

[clarkdo]

Will open another pr

[manniL]

y, I don’t know the new hook pattern decision, is the new pattern corresponding to package? So maybe use hook name as ‘webpack:config’ ?

#6329 (comment)