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i.Core concepts
  • The mental model
  • Which primitive should I use?
  • Anatomy of a primitive
  • Generators and yield*
  • Insertions
  • Typed insertion pipes
  • Exceptions as values
ii.Managing state
  • Local state
  • State machines
  • query
  • Mutations
  • queryParams
  • asyncProcess
  • Selecting
  • Reacting to mutations
  • Collections
  • Collection utilities
  • Persistence
  • GlobalPersisterHandler
  • Pagination placeholders
  • Schema validation
iii.Recommended approaches
  • Inject at the point of use
iv.Structuring the app
  • craftService
  • Service scopes
  • Shaping the public API
  • Abstract services
  • App start
  • Lazy services
  • Server functions
  • craftRegisterFor
  • Target wrapper
v.Routing & type-safe DI
  • Setup
  • CLI automation
  • ESLint rules
  • Route providers
  • Route guards
  • Route exception handling
  • Non-blocking navigation
  • Global error component
  • Route load errors
  • Scaling routes
vi.Components & templates
  • Components
  • Activating the style system
  • Typed styles
  • Defining a design system
  • Tokens and variables
  • Global foundation and fonts
  • Pseudo-elements and animations
  • Axes and the matrix
  • Context obligations
  • Testing visual states
  • Text contrast
  • Visual attestation
  • Template obligations
  • Typed CSS variables
  • Fine-grained reactivity
  • Progressive rendering
  • Directives and .pipe(...)
  • settledValue & pendingNode
  • Accessibility
  • Customization
  • Content projection
  • Styling a component
  • Template migrator
vii.Forms
  • Overview
  • Validators
  • Submitting
  • Nested forms
  • Exception handling
  • Complete examples
viii.Testing
  • Testing services
  • Testing components
  • Type-level tests
  • Browser boundaries
  • Page stability
  • Architecture rules
    • Overview
    • Declarative baseline
    • Unique identities
    • HTTP endpoint ownership
    • Computed purity
    • Dependency cycles
    • Mutation reactions
    • Route DI proofs
    • Route component files
    • Path boundaries
    • Exclusive links
    • Persisted identities
    • insertSelect keys
    • craftEffect and network
    • craftEffect and imperative sync
    • Interactive element names
    • Metric thresholds
    • Server-state loaders
    • Primitive loader requirements
  • Extensible architecture graph
  • Graph insights
  • Craft graph vs Nx
ix.Reactivity utilities
  • craftComputed
  • craftEffect
  • craftMethod
  • source$
  • on$
  • fromEventToSource$
  • sourceFromEvent
  • afterRecomputation
x.Internationalisation
  • Type-safe i18n
  • The catalogue
  • Tokens
  • The runtime
  • With Effect
xi.Deployment (experimental)
  • Overview
  • Manifest reference
  • Diagnostics
  • Providers
  • Alchemy provider
xii.Going further
  • SSR and hydration
  • Effect integration
  • Program operators
  • Pattern matching
  • Observability
  • AI agents
  • Temporal runtime
  1. Testing
  2. Architecture rules
  3. insertSelect keys

Unique insertSelect keys per host#

assertInsertSelectUnique requires each insertSelect key to appear once on a given host primitive:

ts
export function keepSelectedInsertionKeysUnambiguous(
  graph: ArchitectureGraph,
) {
  assertInsertSelectUnique(graph.graph);
}

What it prevents#

An insertion key names a selected slice on its host:

typescript
query(
  'users',
  config,
  insertSelect('cell', selectUserCell),
  insertSelect('cell', selectAnotherCell), // collision
);

Both insertions claim cell. Depending on insertion order, one can replace the other, or consumers can read a type that no longer matches the runtime branch. The failure is especially hard to spot when the two insertions live in separate feature helpers.

The same key on another host is valid#

typescript
state('users', initialUsers, insertSelect('cell', selectUserCell));
state('orders', initialOrders, insertSelect('cell', selectOrderCell));

The key is local to a host. The rule does not impose a useless app-wide naming scheme.

What to do after a failure#

Use a key that describes the selected contract ('summary', 'pagination', 'selectedUser') or merge the two selection behaviours into one insertion when they are really one public slice.

See also#

  • Selecting

  • Typed insertion pipes

←Persisted identitiescraftEffect and network→

On this page

  • What it prevents
  • The same key on another host is valid
  • What to do after a failure
  • See also

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