fix unexpected state resetting #1408

[dotneet]

related issue #1408

getMatchedComponentsInstances() in utils.js returns all components that is matched to new path.
I think this is the root cause of this issue.

getChangedComponentsInstances() in this PR returns components that needs to call data().

This repo can be used to reproduce a problem.
https://github.com/dotneet/nuxt-issue-1408

[dotneet]

Can I do something for your review?

[dotneet]

I found a bug that is caused with a specific case in this PR, and I'm going to fix the bug.
but before that, I want to ask @Atinux if this PR has a possibility to be merged.

[Atinux]

Hi @dotneet

I think it could be merged yes, it seems legit, I let you fix the bug before merging.

[dotneet]

@Atinux Thank you for replying. I've fixed the issue and pushed it now.

[codecov-io]

Codecov Report

Merging #1914 into dev will decrease coverage by 0.31%.
The diff coverage is n/a.

@@            Coverage Diff            @@
##              dev   #1914      +/-   ##
=========================================
- Coverage   89.32%     89%   -0.32%     
=========================================
  Files          14      14              
  Lines         946     946              
=========================================
- Hits          845     842       -3     
- Misses        101     104       +3

Impacted Files	Coverage Δ
lib/core/nuxt.js	93.18% <0%> (-4.55%)	⬇️
lib/core/renderer.js	77.17% <0%> (-0.42%)	⬇️

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[Atinux]

Thank you @dotneet

You're helping use a lot :)

[Atinux]

Ok I see, the problem is when we use query parameters, it does not update automatically now.

[dotneet]

Thank you for feedback.

Exactly. query parameters affects components but we can't detect what components need to be updated. so we need to update all components. this causes state resetting again.

I think that the behavior caused by fixPrepatch() is useful almost but it's not natural when it compared to vue-router's specification. So I propose removing data() evaluation on afterEach hook or making data() evaluation optional.

I think data() evaluation on afterEach hook causes some problems:

1. unexpected state resetting. (Nested Dynamic Route change causes parent route to re-render #1408)
2. make portability low. for example, normally, people believe created(), mounted() are called after data() is called every time.
3. surprise people that are familiar with vue-router.

these problems would produce many bugs.

Do you have any thought on this?

NOTE:
vue-router does not call data() when parameters or query is changed.
https://router.vuejs.org/en/advanced/navigation-guards.html

[Atinux]

I invited you on our Slack so we can talk about it by message :)

[lock]

This thread has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.