Context, actions and utilities

Reference for createContext, the actions helper, shallowCompare, uniqueId and isRecord.

API referenceTypeScriptTry an example

createContext

createContext(initialState, options?) => { use, Provider, Context }

Options: name, metadata, actions, callbacks. See Scoped state with createContext.

Member	Notes
`Provider`	Props: `children`, `value`, `onCreated`, `onMounted`, `onRender`. Also `Provider.makeProviderWrapper(options?)`.
`use(selector?, depsOrOptions?)`	Tuple hook, like a global store. Throws outside a provider.
`use.select(selector)`	Returns the selected value.
`use.api()`	The closest provider’s store API.
`use.actions()`	The closest provider’s actions object.
`use.observable(selector, options?)`	Memoised observable.
`use.createSelectorHook(selector, options?)`	Shared selector hook for this context.
`Context`	The underlying React context.

actions

actions(store, config)      // bind a group of actions to a store now
actions<API>()(config)      // define a template, bind it later with template(api)

Actions in one group call each other with this. The tools passed to the inner function include actions (the store’s own action object). See Actions.

shallowCompare

shallowCompare(a, b) returns true when two values are equal by content one level deep: arrays by item, objects by property. Nested objects are compared by reference. Use it as isEqual.

uniqueId

Call	Result
`uniqueId(prefix?)`	A unique string, optionally prefixed.
`uniqueId.for(prefix)`	A generator of ids with that prefix. TypeScript brands the result type by prefix.
`generator.is(value)`	`true` if `value` is an id from this generator.
`generator.assert(value)`	Throws if it is not.
`uniqueId.for(prefix).strict<Brand>()`	Adds a symbol brand for stricter typing.

isRecord

isRecord(value) accepts non-null objects other than arrays, Map, Set and Date. It also accepts class instances, so use a separate check when you need to restrict a value to plain objects.