Class ProjectionExtension<TItem>

Keeps the list of projected fields and always sends it in the payload (an empty list means "every field").

Example

const projecting = new ProjectionExtension<User>();
projecting.setProjections([{ field: "id" }, { field: "lastName" }]);
// payload.projections: [{ field: "id" }, { field: "lastName" }]

Type Parameters

TItem = Any
Type of the items.

Hierarchy (View Summary)

DataSourceExtension<TItem, ProjectionExtensionEvents<TItem>>
- ProjectionExtension

Implements

IProjectionExtension<TItem>

Index

Constructors

constructor

new ProjectionExtension<TItem = any>(
options?: DataSourceExtensionOptions,
): ProjectionExtension<TItem>
Type Parameters
- TItem = any
  Type of the items.
Parameters
- Optionaloptions: DataSourceExtensionOptions
  Debounce of the projectionsChange event.
Returns ProjectionExtension<TItem>
Overrides DataSourceExtension.constructor
- Defined in src/data-source/projection/models.ts:31

Properties

`Protected` `Readonly`_changeDelay

_changeDelay: number

`Protected`_eventBus

_eventBus: EventBus<ProjectionExtensionEvents<TItem>>

Bus used to register handlers and to raise the events.

`Protected`_projections

_projections: List<Projection<TItem>> = []

Accessors

hasProjections

get hasProjections(): boolean
true when at least one projection is set.

Returns boolean
Implementation of IProjectionExtension.hasProjections
- Defined in src/data-source/projection/models.ts:35

projections

get projections(): List<Projection<TItem>>
Current projections, in insertion order; empty means "every field".

Returns List<Projection<TItem>>
Implementation of IProjectionExtension.projections
- Defined in src/data-source/projection/models.ts:38

Methods

`Protected`_scheduleChange

_scheduleChange(): void
Schedules the *Change event after the quiet time, restarting the wait if one is already pending.

Returns void
Inherited from DataSourceExtension._scheduleChange
- Defined in src/data-source/extensions/models.ts:65

`Protected`_triggerChange

_triggerChange(): void
Raises the *Change event of the extension.

Returns void
Overrides DataSourceExtension._triggerChange
- Defined in src/data-source/projection/models.ts:71

addProjection

addProjection(projection: Projection<TItem>): void
Appends a projection.
Parameters
- projection: Projection<TItem>
  Projection to add; ignored, without events, when a projection on the same field already exists.
Returns void
Implementation of IProjectionExtension.addProjection
- Defined in src/data-source/projection/models.ts:42

buildPayload

buildPayload(
payload: DataSourcePayload<TItem>,
): Promise<DataSourcePayload<TItem>>
Adds the contribution of the extension to the payload. Build phase, run in the order of the keys and completed before any item is read.
Parameters
- payload: DataSourcePayload<TItem>
  Payload built by the previous extensions.
Returns Promise<DataSourcePayload<TItem>>
the payload for the next extension.
Implementation of IProjectionExtension.buildPayload
- Defined in src/data-source/projection/models.ts:65

clearProjections

clearProjections(): void
Removes every projection.

Returns void
Implementation of IProjectionExtension.clearProjections
- Defined in src/data-source/projection/models.ts:48

dispose

dispose(): Promise<void>
Cancels the pending *Change event and removes every handler.

Returns Promise<void>
Implementation of IProjectionExtension.dispose

Inherited from DataSourceExtension.dispose
- Defined in src/data-source/extensions/models.ts:51

on

on<TKey extends string>(
event: TKey,
handler: EventHandler<ProjectionExtensionEvents<TItem>, TKey>,
): IDisposable
Registers a handler for an event.
Type Parameters
- TKey extends string
  Name of the event to listen to.
Parameters
- event: TKey
  Event to subscribe to.
- handler: EventHandler<ProjectionExtensionEvents<TItem>, TKey>
  Callback invoked every time event is raised.
Returns IDisposable
a subscription; dispose it to remove this single handler.
Implementation of IProjectionExtension.on

Inherited from DataSourceExtension.on
- Defined in node_modules/@mantlebee/ts-core/dist/src/subscriptions/subscribable/models.d.ts:33

removeProjection

removeProjection(field: KeyOf<TItem>): void
Removes the projection on a field, if any.
Parameters
- field: KeyOf<TItem>
  Field no longer projected.
Returns void
Implementation of IProjectionExtension.removeProjection
- Defined in src/data-source/projection/models.ts:53

setProjections

setProjections(projections: List<Projection<TItem>>): void
Replaces every projection.
Parameters
- projections: List<Projection<TItem>>
  New projections, taken as they are (duplicates are not removed).
Returns void
Implementation of IProjectionExtension.setProjections
- Defined in src/data-source/projection/models.ts:58

Class ProjectionExtension<TItem>

Example

Type Parameters

Hierarchy (View Summary)

Implements

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Type Parameters

Parameters

Returns ProjectionExtension<TItem>

Properties

Protected Readonly_changeDelay

Protected_eventBus

Protected_projections

Accessors

hasProjections

Returns boolean

projections

Returns List<Projection<TItem>>

Methods

Protected_scheduleChange

Returns void

Protected_triggerChange

Returns void

addProjection

Parameters

Returns void

buildPayload

Parameters

Returns Promise<DataSourcePayload<TItem>>

clearProjections

Returns void

dispose

Returns Promise<void>

on

Type Parameters

Parameters

Returns IDisposable

removeProjection

Parameters

Returns void

setProjections

Parameters

Returns void

Settings

On This Page

`Protected` `Readonly`_changeDelay

`Protected`_eventBus

`Protected`_projections

`Protected`_scheduleChange

`Protected`_triggerChange