🥶 Slightly BelowZero

[janjakubnanista]

In this PR

A stub of a BelowZero-like functionality for UA configuration. It builds around a concept of Property - a structure that has:

• a current/actual value, obtained by a getter
• a desired value, obtained by a desired value getter
• a way to transition between the actual and desired value, represented by a setter

Property itself does not impose any restrictions on any of these, neither structural nor executional. This means a property can:

• Work with a single primitive value on a contract directly
• Work with multiple values on a contract
• Submit values to the contract directly
• Populate transactions and pass them on for further execution
• ... you name it it will do it

Properties define their context - a value or set of values that they require to be able to get/set their state. The context is strongly typed and required to evaluate a property, i.e. to turn a property into a PropertyState:

const property = createProperty({ ... })

// Some properties might work with no context
const state = property();

// Other require some simple context
const state = property(someContract);

// And other might need more information still
const state = property(someContract, someParameter, someOtherParameter);

Result of the evaluation is a PropertyState that comes in two varieties:

• Configured represents a state where desired and actual values match, no action needed
• Misconfigured represents a state where an action is needed to synchronize current and desired states

To ease the work with these two, isConfigured and isMisconfigured utilities are provided:

const state = property(someContract);

if (isMisconfigured(state)) {
  // log something or whatnot
}