Gate

A precondition attached to a handler. It refuses by throwing a Notice (a reply) or a Silence (a drop with no reply), and passes by returning. Ctx is the context it requires, so a gate that reads a field absent on a handler's context is rejected at compile time. Name is captured as a literal so a mismatch error can name the gate. Build one with defineGate or defineEffectGate.

See also:defineGate

interface Gate<
    Ctx extends GateContextBase = GateContextBase,
    Name extends string = string
>

// a factory returning a typed, agnostic gate
function MyGate(): Gate<GateContextBase, 'MyGate'> {
    return defineGate('MyGate', (ctx) => {
        if (shouldRefuse(ctx)) throw new MyNotice();
    });
}

Properties

name

Methods

check()

Ctx

The context the gate requires. A field missing from it is a compile error.

Ctx extends GateContextBase = GateContextBase

Name

The gate's literal name, named in a mismatch error.

Name extends string = string

name

The gate's name, surfaced in a mismatch error and joined by the combinators.

readonly name: Name

check()

Reads the context and refuses by throwing a Notice or a Silence, or passes by resolving.

async check(ctx: Ctx): Promise<void>