Vue 2 with Volar, Options API, & defineComponent. Vue interface properties throw unavaialble errors, but still exist at runtime.

[douglasg14b]

When using Volar, with Vue 2, TS, and the Options API (Trying to move components over bit by bit). The compiler is showing that this.$options or this.$router does not exist inside computed's. It shows it does exist inside of methods.

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Edit:

Another look seems to indicate that this only happens if the variable that is being assigned is returned...?

// No Error
const truncated = this.$options?.filters?.ellipsis(branchName, 20)

// No Error
const truncated1 = branchName?.length > 20 ? this.$options?.filters?.ellipsis(branchName, 20) : '' ?? ''

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// No Error
const truncated = this.$options?.filters?.ellipsis(branchName, 20)

// Error "Property '$options' does not exist on type"
// Error: "'truncated1 ' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer."
const truncated1 = branchName?.length > 20 ? this.$options?.filters?.ellipsis(branchName, 20) : '' ?? ''

return truncated1

// Error "Property '$options' does not exist on type"
// Error: "'truncated' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer."
const truncated = this.$options?.filters?.ellipsis(branchName, 20)

// Error "Property '$options' does not exist on type"
// Error: "'truncated1' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer."
const truncated1 = branchName?.length > 20 ? this.$options?.filters?.ellipsis(branchName, 20) : '' ?? ''

return truncated 
return truncated1 // Even though this is unreachable it still triggers the above error

If I annotate the type, there is no error anymore....?

// No Error
const truncated1: string = branchName?.length > 20 ? this.$options?.filters?.ellipsis(branchName, 20) : '' ?? ''

return truncated 1

However, this still exists at runtime, so it's actually available even if the type checking thinks it isn't.

How should this be resolved while using the Options API?

Pmuch none of these show as available in computed: