how do I add a field to my exo / durable object?

[dckc]

While working on upgrading the smart wallet to handle non-vbank purses (#7226, #8071), I ran into Error: Cannot add property brandToPurses, object is not extensible at this line:

          this.state.brandToPurses = brandToPurses;

I suppose this.state is hardened. What do I: do?

[dckc]

@erights replied:

For the current problem, I suggest creating a separate durable WeakMapStore whose keys are the durable exo instances in question. Classic OO soft field technique using a weak side table.

That seems to work:

2023-07-25 19:36 61da1bd chore: use side table for new purse storage

Here's hoping for time to elaborate a bit.