groups-not-installed

[wizzard] step "<id>" is a group, but no traversal is installed. Without one the
engine walks flat flows only. Pass groups from @wizzard-packages/core/groups to
createWizard. …/errors/groups-not-installed

A GroupStep is a sub-flow, and walking one means pushing frames onto the stack, evaluating repeat.over, keying its items and deciding what the end of a child flow means at that depth. That is several hundred bytes of machinery, and a flow with no sub-flows would carry it for nothing, so it ships as a separate entry and is handed to the engine rather than imported by it.

import { createWizard } from '@wizzard-packages/core';
import { groups } from '@wizzard-packages/core/groups';

const wizard = createWizard({ flow, groups, subFlows });

subFlows is only needed when a GroupStep.flow is a string: it maps that string to the definition it names. A group whose flow is the definition itself resolves without it.

The check runs in createWizard and again in patchFlow, which are the two places a flow arrives, so it fails before the first render rather than on the first next(). Without it the failure is silent and late: the step resolves, reachability includes it, and the binding is asked to render a step type that has no view.