Fix undefined outros variable in transitions

[ryu-man]

This error occures in the method transition_out when trying to use a component from external dependancy and wrapping it inside a <div in:{...} out:{...}/>.

• The tests with npm test and lint the project with npm run lint was succesful

Error message: Cannot read property 'c' of undefined.

[dummdidumm]

Is it possible to add a otherwise failing test?

[ryu-man]

I solved it by adding an if(outros !=undefined) in svelte internal code before calling the variable , but i would say that in the current version (3.29.7) i am not seeing this problem any more.

[nergmada]

I am experiencing this issue in 3.29.7, can someone advise if this is going to merge?

[ryu-man]

@nergmada I use the latest version of svelte and I no longer see this problem, try to update your svelte package and check if it still exists.

[nergmada]

So I did a bunch more reading, and I think my issue (and maybe your issue because i'm guessing you compile your svelte components down to a single index.js with webpack at package/install time) is to do with how svelte/internals gets bundled with it. I don't entirely understand the inner workings of svelte, but my guess is that svelte internals (despite it's name) isn't completely self contained so two instances of it cause problems

I've linked the thread here. I've noticed this issue doesn't occur all the time and has a seemingly non-deterministic behaviour to it, because I don't always have an issue with destroying my compiled components

#3671 (comment)

[antony]

This sounds like your config is not dedupe ing Svelte correctly, so it is a problem with your bundler configuration - I don't believe it needs patching in Svelte itself.