Class Component

Components are used to attach functionality on a Entity. Components can receive update events each frame, and expose properties to the PlayCanvas Editor.

Hierarchy (View Summary)

Constructors

constructor

Properties

entity system

Accessors

enabled

Methods

fire hasEvent off on once

Constructors

constructor

Properties

entity

entity: Entity

The Entity that this Component is attached to.

system

system: ComponentSystem

The ComponentSystem used to create this Component.

Accessors

enabled

Methods

fire

  • fire(
        name: string,
        arg1?: any,
        arg2?: any,
        arg3?: any,
        arg4?: any,
        arg5?: any,
        arg6?: any,
        arg7?: any,
        arg8?: any,
    ): EventHandler

  • Fire an event, all additional arguments are passed on to the event listener.

    Parameters

    • name: string

      Name of event to fire.

    • Optionalarg1: any

      First argument that is passed to the event handler.

    • Optionalarg2: any

      Second argument that is passed to the event handler.

    • Optionalarg3: any

      Third argument that is passed to the event handler.

    • Optionalarg4: any

      Fourth argument that is passed to the event handler.

    • Optionalarg5: any

      Fifth argument that is passed to the event handler.

    • Optionalarg6: any

      Sixth argument that is passed to the event handler.

    • Optionalarg7: any

      Seventh argument that is passed to the event handler.

    • Optionalarg8: any

      Eighth argument that is passed to the event handler.

    Returns EventHandler

    Self for chaining.

    Example

    obj.fire('test', 'This is the message');

hasEvent

  • hasEvent(name: string): boolean

  • Test if there are any handlers bound to an event name.

    Parameters

    • name: string

      The name of the event to test.

    Returns boolean

    True if the object has handlers bound to the specified event name.

    Example

    obj.on('test', function () { }); // bind an event to 'test'
    obj.hasEvent('test'); // returns true
    obj.hasEvent('hello'); // returns false

off

  • off(name?: string, callback?: HandleEventCallback, scope?: object): EventHandler

  • Detach an event handler from an event. If callback is not provided then all callbacks are unbound from the event, if scope is not provided then all events with the callback will be unbound.

    Parameters

    • Optionalname: string

      Name of the event to unbind.

    • Optionalcallback: HandleEventCallback

      Function to be unbound.

    • Optionalscope: object

      Scope that was used as the this when the event is fired.

    Returns EventHandler

    Self for chaining.

    Example

    const handler = function () {
    };
    obj.on('test', handler);

    obj.off(); // Removes all events
    obj.off('test'); // Removes all events called 'test'
    obj.off('test', handler); // Removes all handler functions, called 'test'
    obj.off('test', handler, this); // Removes all handler functions, called 'test' with scope this

on

  • on(name: string, callback: HandleEventCallback, scope?: object): EventHandle

  • Attach an event handler to an event.

    Parameters

    • name: string

      Name of the event to bind the callback to.

    • callback: HandleEventCallback

      Function that is called when event is fired. Note the callback is limited to 8 arguments.

    • Optionalscope: object = ...

      Object to use as 'this' when the event is fired, defaults to current this.

    Returns EventHandle

    Can be used for removing event in the future.

    Example

    obj.on('test', function (a, b) {
        console.log(a + b);
    });
    obj.fire('test', 1, 2); // prints 3 to the console

    Example

    const evt = obj.on('test', function (a, b) {
        console.log(a + b);
    });
    // some time later
    evt.off();

once

  • once(name: string, callback: HandleEventCallback, scope?: object): EventHandle

  • Attach an event handler to an event. This handler will be removed after being fired once.

    Parameters

    • name: string

      Name of the event to bind the callback to.

    • callback: HandleEventCallback

      Function that is called when event is fired. Note the callback is limited to 8 arguments.

    • Optionalscope: object = ...

      Object to use as 'this' when the event is fired, defaults to current this.

    Returns EventHandle

    • can be used for removing event in the future.

    Example

    obj.once('test', function (a, b) {
        console.log(a + b);
    });
    obj.fire('test', 1, 2); // prints 3 to the console
    obj.fire('test', 1, 2); // not going to get handled

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