Notify collection association states on membership changes

[bemky]

What

record.state('someCollection') never notified its listeners. viking mutates a collection association's target array in place (setTarget splices it and re-pushes), so the plugin handed State.set the same array reference on every change:

this.states[attribute].set(this.association(attribute).target);

State.set guards on oldValue != newValue, so with an unchanged reference the dispatch was skipped every time. A binding on a collection state only ever showed what it was first rendered with — a Comments (n) header, for example, kept its original count no matter how many comments were added or deleted.

Fix

Snapshot the array so its identity changes:

const read = () => Array.isArray(association.target) ? [...association.target] : association.target;

belongsTo is unchanged — its target is a record rather than an array, and it already changes identity on assignment, so it keeps passing straight through. That's what the Array.isArray check preserves.

One consequence worth noting: a collection state's value is now a detached copy rather than the live target, so it reflects membership as of the last afterAdd/afterRemove. Mutations that dispatch neither (e.g. a setTarget that only reorders the same members) won't refresh it — previously nothing refreshed it at all after the first render.

Test

Added a hasMany case to test/vikingTest.js asserting listeners fire and the value tracks membership. It fails on master with 0 == 1 (listener never called) and passes here.

npm test: 37 passing, 0 failing — including the existing belongsTo cases.

🤖 Generated with Claude Code