Class CoreElement<E>

CoreElement

A lightweight base class that provides two orthogonal utilities commonly needed by UI or domain objects:

Named timers (wraps setTimeout / setInterval by name so they can be started, stopped, and cleared by string identifier), and
A typed eventing surface (lazy-initialised EventSource) for attaching, detaching and firing events.

The class is generic over an EventMap E which maps event name keys to the payload type for that event. This enables compile-time type safety for listeners and fired events.

Template parameters:

Type Parameters

E extends EventMap = EventMap
An EventMap-shaped type that maps event keys to the event payload types.

Timer semantics:
- Timers are referenced by a string name. Each instance of CoreElement maintains its own map of timers.
- Starting a timer with a name that is already present will stop the previous timer first.
- setTimeout(name, ms, callback) creates a single-shot timer (uses global setTimeout).
- setInterval(name, ms, callback) creates a repeating timer (uses global setInterval).
- clearTimeout(name) and clearInterval(name) both stop and remove the timer with the given name (they are aliases for the same internal stop logic).
- clearTimeouts() will stop and remove all timers currently tracked by the instance.
- The underlying timer handles are encapsulated; callers only interact via the string name.
Event semantics:
- Event support is provided via a lazily-initialised EventSource instance internal to the CoreElement. The EventSource is created on first use (first call to on()).
- on(name, listener) registers a listener for the given event name and returns a small subscription object exposing an off() method for convenience.
- off(name, listener) removes a previously-registered listener (no-op if there is no EventSource or listener).
- fire(name, ev) will dispatch the given payload to all listeners registered for that event name (no-op if there is no EventSource).
- Listener and event payload types are enforced by the generic E.
Threading / reentrancy / error handling:
- Timer callbacks execute via the platform timer mechanisms (setTimeout/setInterval). Any exceptions thrown by callbacks will propagate according to the environment's timer semantics (typically uncaught unless handled by the callback).
- The class uses console.assert to validate non-null listeners on public attach/detach methods; callers should avoid passing undefined/null listeners. Example:
```
// Strongly-typed events
interface MyEvents { loaded: { ok: boolean }, tick: number }
class MyElement extends CoreElement<MyEvents> {}

const el = new MyElement();
const sub = el.on("loaded", e => console.log(e.ok));
el.fire("loaded", { ok: true });
sub.off(); // convenience to remove listener

// Timers
el.setInterval("poll", 1000, () => el.fire("tick", Date.now()));
el.clearInterval("poll");
```

Hierarchy (View Summary)

CoreElement
- Component
- Application
- DataProxy
- DataView
- Store

Index

Constructors

constructor

Methods

clearInterval clearTimeout clearTimeouts fire off on setInterval setTimeout

Constructors

constructor

new CoreElement<E extends EventMap = EventMap>(): CoreElement<E>
Type Parameters
- E extends EventMap = EventMap
  An EventMap-shaped type that maps event keys to the event payload types.
  
  Timer semantics:
  
  Timers are referenced by a string name. Each instance of CoreElement maintains its own map of timers.
  
  Starting a timer with a name that is already present will stop the previous timer first.
  
  setTimeout(name, ms, callback) creates a single-shot timer (uses global setTimeout).
  
  setInterval(name, ms, callback) creates a repeating timer (uses global setInterval).
  
  clearTimeout(name) and clearInterval(name) both stop and remove the timer with the given name (they are aliases for the same internal stop logic).
  
  clearTimeouts() will stop and remove all timers currently tracked by the instance.
  
  The underlying timer handles are encapsulated; callers only interact via the string name.
  
  Event semantics:
  
  Event support is provided via a lazily-initialised EventSource instance internal to the CoreElement. The EventSource is created on first use (first call to on()).
  
  on(name, listener) registers a listener for the given event name and returns a small subscription object exposing an off() method for convenience.
  
  off(name, listener) removes a previously-registered listener (no-op if there is no EventSource or listener).
  
  fire(name, ev) will dispatch the given payload to all listeners registered for that event name (no-op if there is no EventSource).
  
  Listener and event payload types are enforced by the generic E.
  
  Threading / reentrancy / error handling:
  
  Timer callbacks execute via the platform timer mechanisms (setTimeout/setInterval). Any exceptions thrown by callbacks will propagate according to the environment's timer semantics (typically uncaught unless handled by the callback).
  
  The class uses console.assert to validate non-null listeners on public attach/detach methods; callers should avoid passing undefined/null listeners. Example:
  
  // Strongly-typed events interface MyEvents { loaded: { ok: boolean }, tick: number } class MyElement extends CoreElement<MyEvents> {} const el = new MyElement(); const sub = el.on("loaded", e => console.log(e.ok)); el.fire("loaded", { ok: true }); sub.off(); // convenience to remove listener // Timers el.setInterval("poll", 1000, () => el.fire("tick", Date.now())); el.clearInterval("poll");
Returns CoreElement<E>

Methods

clearInterval

clearInterval(name: string): void
Clears a previously set interval.
Parameters
- name: string
  The name of the interval to clear.
Returns void

See
setInterval
- Defined in src/core/core_element.ts:146

clearTimeout

clearTimeout(name: string): void
Clears a previously set timeout.
Parameters
- name: string
  The name of the timeout to clear.
Returns void

See
setTimeout
- Defined in src/core/core_element.ts:124

clearTimeouts

clearTimeouts(): void
Clears all timeouts and intervals currently managed by this instance. This stops all scheduled callbacks and removes their references.

Returns void

See
setTimeout
- Defined in src/core/core_element.ts:155

fire

fire<K extends string | number | symbol>(name: K, ev: E[K]): void
Dispatches an event with a given name and payload to all registered listeners. If no listeners are registered for the event name, or if no EventSource has been initialized, this method does nothing.
Type Parameters
- K extends string | number | symbol
Parameters
- name: K
  The name of the event to fire.
- ev: E[K]
  The payload (event object) to pass to the listeners.
Returns void
See
- on
- off
- Defined in src/core/core_element.ts:217

off

off<K extends string | number | symbol>(
name: K,
listener: (ev: E[K]) => void,
): void
Removes a previously registered event listener. If the listener was not found or no events were registered, this method does nothing.
Type Parameters
- K extends string | number | symbol
Parameters
- name: K
  The name of the event from which to remove the listener.
- listener: (ev: E[K]) => void
  The specific listener function to remove.
Returns void
See
- on
- fire
- Defined in src/core/core_element.ts:200

on

on<K extends string | number | symbol>(
name: K,
listener: (ev: E[K]) => void,
): { off: () => void }
Registers an event listener for a specific event name. The listener will be invoked when an event with the given name is fired. Returns an object with an off() method, which can be used to conveniently remove this specific listener.
Type Parameters
- K extends string | number | symbol
Parameters
- name: K
  The name of the event to listen for.
- listener: (ev: E[K]) => void
  The callback function to execute when the event is fired.
Returns { off: () => void }
An object containing an off() method to unsubscribe the listener.

See
fire attach to an event
- Defined in src/core/core_element.ts:176

setInterval

setInterval(name: string, ms: number, callback: () => void): void
Sets an interval that repeatedly executes a callback function after a specified delay. If a timeout with the same name already exists, it will be cleared before the new one is set.
Parameters
- name: string
  A unique string identifier for this timeout.
- ms: number
  The delay in milliseconds before the callback is executed.
- callback: () => void
  The function to execute after the delay.
Returns void
- Defined in src/core/core_element.ts:136

setTimeout

setTimeout(name: string, ms: number, callback: () => void): void
Sets a timeout that executes a callback function after a specified delay. If a timeout with the same name already exists, it will be cleared before the new one is set.
Parameters
- name: string
  A unique string identifier for this timeout.
- ms: number
  The delay in milliseconds before the callback is executed.
- callback: () => void
  The function to execute after the delay.
Returns void
- Defined in src/core/core_element.ts:114

Class CoreElement<E>

Type Parameters

Hierarchy (View Summary)

Index

Constructors

Methods

Constructors

constructor

Type Parameters

Returns CoreElement<E>

Methods

clearInterval

Parameters

Returns void

See

clearTimeout

Parameters

Returns void

See

clearTimeouts

Returns void

See

fire

Type Parameters

Parameters

Returns void

See

off

Type Parameters

Parameters

Returns void

See

on

Type Parameters

Parameters

Returns { off: () => void }

See

setInterval

Parameters

Returns void

setTimeout

Parameters

Returns void

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