Immutable prop warning for various components

[brettchalupa]

Stencil version: (run npm list @stencil/core from a terminal/cmd prompt and paste output below):

@stencil/[email protected]
@stencil/[email protected]

I'm submitting a ... (check one with "x") [x] bug report [ ] feature request [ ] support request => Please do not submit support requests here, use one of these channels: https://forum.ionicframework.com/ or https://stencil-worldwide.slack.com

Current behavior:

dozens of console warnings for mutable props being changed are output to the console

"@Prop() \"root\" on <stencil-route-link> is immutable but was modified from within the component.
More information: https://stenciljs.com/docs/properties#prop-mutability"

Expected behavior:

no console warnings

Steps to reproduce:

1. create a new stencil app or upgrade to stencil 2.4.0, using app from https://stenciljs.com/docs/getting-started yields the results
2. open the app in the browser
3. open the web tools

Other information:

Screenshot:

Commit that introduced the warning: https://github.com/ionic-team/stencil/commit/9c18fa0da217be0bd9e28672f2a0b3c9599de2db

I think the fix would be change the code for these props (example) to be mutable, e.g.

@Prop({ mutable: true }) history?: RouterHistory;
@Prop({ mutable: true }) location?: LocationSegments;
@Prop({ mutable: true }) root?: string;

I'm happy to submit a PR if that's accurate, but I'm not 100% confident in being able to cover the scope of these changes. Thanks!

[fohlin]

Good bug report and a shame that it's not getting any attention. Should encourage people willing to do PRs!

[MrGowdy]

Issue still persists. These errors also clutter the 'npm run test' results. It took me a while to figure out that I wasn't doing anything as a new Stencil developer. A PR would be much appreciated!

[ssurabhi10]

Facing the same issue! A PR would be much appreciated!

[gregorypratt]

My assumption is that v2 is on it's way so this gets shelved in favour of that re-write

[MrGowdy]

@gregorypratt I hope you are right.

In the meantime, does anyone know if it's possible to temporarily solve this issue locally and prevent these warnings? It is really cluttering my console while developing.

[Overthane]

@gregorypratt I hope you are right.

In the meantime, does anyone know if it's possible to temporarily solve this issue locally and prevent these warnings? It is really cluttering my console while developing.

I just went into node_modules/@stencil/router/collection/components/ and changed mutable: false to mutable: true for the appropriate Props, in the appropriate components.

[MrGowdy]

Thank you so much @Overthane. This solved the issue for me. I managed to get myself quite lost within the node_modules...

[bleuscyther]

It seems to be because of the way Stencil State Tunnel shares state values across the hierarchy.

They would normally use events (with reserved names) to do that, but I am guessing that would be out of the scope of Stencil, at least in terms of the spirit behind it. That could be the reason why they moved it to the community repo, to separate the concerns: build cross-library components vs building a fully functional app/website.

Route https://github.com/stencil-community/stencil-router/blob/2580a320b68f3ad8a129d4bbd2c81c5dc6ef87cd/packages/router/src/components/route/route.tsx#L123-L128

Route-Link

https://github.com/stencil-community/stencil-router/blob/2580a320b68f3ad8a129d4bbd2c81c5dc6ef87cd/packages/router/src/components/route-link/route-link.tsx#L117-L121

Switch

https://github.com/stencil-community/stencil-router/blob/2580a320b68f3ad8a129d4bbd2c81c5dc6ef87cd/packages/router/src/components/switch/switch.tsx#L127-L130

Redirect https://github.com/stencil-community/stencil-router/blob/2580a320b68f3ad8a129d4bbd2c81c5dc6ef87cd/packages/router/src/components/redirect/redirect.tsx#L32-L35

I switched to the History API (1) (2)to handle the routing logic 😅. It feels less like using React or Angular

[safaalai]

An addition to @Overthane's answer:

I use cloudflare pages where when I push my code to Github, the server kicks in, does an install, pulls the code and builds everything. Of course, that means that all my changes in node_modules are lost.

So based on this StackOverflow answer I do the following:

1. Make the changes as suggested by @Overthane
2. Run npm install patch-package --save-dev
3. run npx patch-package @stencil/router
4. check in to git the patch file created in the <my-project>/patches directory
5. Add the line "postinstall": "npx patch-package" to the script section of package.json