{String: String} broken in Flow Playground

Whenever I attempt to use the {String: String} input for transactions I get this error
Error: GraphQL error: failed to decode argument 0: failed to decode value: invalid JSON Cadence structure
I brought the code down to its simplest form

transaction(metadata: {String: String}) {
prepare(acct: AuthAccount) {}
execute {

And I use the simplest JSON Cadence object straight from the documentation
{"type": "Void"}

But no matter what I do I still get the same error.
I am trying to build a resource that utilizes JSON for it’s metadata, so any help here would be huge.

1 Like

i have the exact same problem

did you manage to find a solution to this?

quite sadly, no. It seem that the playground itself does not support cadence objects. But I have no idea why.

Thank you for reporting this!

I’ve opened a bug report for it: Complex arguments are not working · Issue #141 · onflow/flow-playground · GitHub