🏚 Check if the 0x address is broken about old-balance-ios

[einsteinx2]

So we do some basic format checking already (though without feedback). I check if it starts with either 0x and is exactly 42 characters long or starts with ENS and is at least 4 characters long. Will need to discuss what options we have for better validation and how you want to present it to the user. For now I'll hold off on this.

[wolffan]

Make a request and check if that address has tokens? spinner while network request is performed and not enable button until comes back (bonus point if we pre-save that info so user don't need to wait again)

[einsteinx2]

yeah exactly what I was thinking (I meant to paste in my commend from Discord). We need to load the data anyway so we could load it first.

[einsteinx2]

My discord comment:

From what I found searching it seems like we only have three options:

1. use a simple regex to verify it is a possible address, but not necessarily an actual address

2. use the upper/lowercase format for addresses that includes essentially a built in checksum (but that's not great because many addresses aren't formatted that way)

3. use an API to see if the eth wallet exists on the network (ok for our use case since we aren't sending eth so wallets will always be pre-existing, but not sure if we want to rely on another 3rd party API, though maybe we could use the existing ethporer or other eth api we get the wallet details for that, i.e. if the api returns the wallet has nothing, don't add it or something)

I'm thinking 3 is the way to go as @wolffan suggested.

[einsteinx2]

For now, handled by #61