DX overhaul — adding a slice should be like drinking water #59

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opened 2026-02-21 22:43:22 +00:00 by ash · 0 comments

ash commented

2026-02-21 22:43:22 +00:00

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Vision

Adding a state change slice, state view slice, or automation slice should be the simplest thing in the world. One-of-a-kind DX. If a new dev can't understand it in 5 minutes, we failed.

Current State

The order-system example is decent but could be simpler. Key friction points to audit:

How many lines to define a minimal state change slice?
How many types need to be understood upfront?
Is the Decider generic signature intimidating? Decider[S, C, E] is 3 type params
Are Given/When/Then test helpers discoverable and exported?
Missing test files for cancel_order, ship_order examples

Goals

State Change Slice (command → events)

Should feel like:

var CreateOrder = eskit.StateChange[OrderState, CreateOrderCmd]{
    Decide: func(s OrderState, c CreateOrderCmd) ([]Event, error) { ... },
    Evolve: evolve,
}

State View (events → read model)

Should feel like:

var OrderList = eskit.StateView[OrderSummary]{
    EventTypes: []string{"OrderCreated", "OrderShipped"},
    Handle: func(state *OrderSummary, event Event) { ... },
}

Automation (event → command)

Should feel like:

var AutoShip = eskit.Automation{
    Trigger: "PaymentProcessed",
    Execute: func(ctx context.Context, e Event) error { ... },
}

Acceptance

Audit current lines-of-code for each slice type
Reduce boilerplate to absolute minimum
All 3 patterns (state change, state view, automation) have dead-simple examples
Test helpers exported and documented
README quick-start shows all 3 patterns in <50 lines total
Every example file has tests

## Vision Adding a state change slice, state view slice, or automation slice should be the simplest thing in the world. One-of-a-kind DX. If a new dev can't understand it in 5 minutes, we failed. ## Current State The order-system example is decent but could be simpler. Key friction points to audit: - How many lines to define a minimal state change slice? - How many types need to be understood upfront? - Is the Decider generic signature intimidating? `Decider[S, C, E]` is 3 type params - Are Given/When/Then test helpers discoverable and exported? - Missing test files for cancel_order, ship_order examples ## Goals ### State Change Slice (command → events) Should feel like: ```go var CreateOrder = eskit.StateChange[OrderState, CreateOrderCmd]{ Decide: func(s OrderState, c CreateOrderCmd) ([]Event, error) { ... }, Evolve: evolve, } ``` ### State View (events → read model) Should feel like: ```go var OrderList = eskit.StateView[OrderSummary]{ EventTypes: []string{"OrderCreated", "OrderShipped"}, Handle: func(state *OrderSummary, event Event) { ... }, } ``` ### Automation (event → command) Should feel like: ```go var AutoShip = eskit.Automation{ Trigger: "PaymentProcessed", Execute: func(ctx context.Context, e Event) error { ... }, } ``` ## Acceptance - [ ] Audit current lines-of-code for each slice type - [ ] Reduce boilerplate to absolute minimum - [ ] All 3 patterns (state change, state view, automation) have dead-simple examples - [ ] Test helpers exported and documented - [ ] README quick-start shows all 3 patterns in <50 lines total - [ ] Every example file has tests