onError is undocumented

[dancrumb]

Version

3.0.1

Reproduction link

https://router.vuejs.org/en/installation.html#

Steps to reproduce

Look at the docs
Try to find a mention of onError that describes appropriate usage.
Fail to find it.

What is expected?

Documentation of this method

What is actually happening?

Documentation of this method is not present

[kwbBaker]

Why was this closed? I've just been dealing with this exact same issue in vue-router 3.0.1 and can assure you it is not fixed. The documentation covers onError here: https://router.vuejs.org/api/#router-onerror but there is absolutely no mention of any expected usage, and it even suggests that it is purely a no-argument callback that you must provide. I see from examples and discussions on-line that people treat it as a callback that is to take some sort of error parameter when it is called, but the documentation is completely silent on the matter. This is all it says:

router.onError

Signature:

router.onError(callback)

Register a callback which will be called when an error is caught during a route navigation. Note for an error to be called, it must be one of the following scenarios:

The error is thrown synchronously inside a route guard function;

The error is caught and asynchronously handled by calling next(err) inside a route guard function;

An error occurred when trying to resolve an async component that is required to render a route.

[candu]

Agree with @kwbskf here - the documentation could be more specific as to what's expected here.

For anyone else coming to this issue: I don't unfortunately have time right now to navigate the vue-router docs PR process, but I did track down the expected callback signature in router.d.ts:

type ErrorHandler = (err: Error) => void
onError(cb: ErrorHandler): void