Skip to main content
Version: 4.4.1

Component

class Component

A class used to manage events in a component

Properties
Methods

Properties#

VERSION#

static

Version info string

Type: string

Component.VERSION; // ex) 3.0.0

Methods#

trigger#

Trigger a custom event.

Returns: this

  • An instance of the component itself
PARAMETERTYPEOPTIONALDEFAULTDESCRIPTION
eventstring | ComponentEventThe name of the custom event to be triggered or an instance of the ComponentEvent
paramsArray<any> | $ts:...Event data to be sent when triggering a custom event
import Component, { ComponentEvent } from "@egjs/component";
class Some extends Component<{
beforeHi: ComponentEvent<{ foo: number; bar: string }>;
hi: { foo: { a: number; b: boolean } };
someEvent: (foo: number, bar: string) => void;
someOtherEvent: void; // When there's no event argument
}> {
some(){
if(this.trigger("beforeHi")){ // When event call to stop return false.
this.trigger("hi");// fire hi event.
}
}
}
const some = new Some();
some.on("beforeHi", e => {
if(condition){
e.stop(); // When event call to stop, `hi` event not call.
}
// `currentTarget` is component instance.
console.log(some === e.currentTarget); // true
typeof e.foo; // number
typeof e.bar; // string
});
some.on("hi", e => {
typeof e.foo.b; // boolean
});
// If you want to more know event design. You can see article.
// https://github.com/naver/egjs-component/wiki/How-to-make-Component-event-design%3F

once#

Executed event just one time.

Returns: this

  • An instance of the component itself
PARAMETERTYPEOPTIONALDEFAULTDESCRIPTION
eventNamestring | $ts:...The name of the event to be attached or an event name - event handler mapped object.
handlerToAttachfunction | $ts:...✔️The handler function of the event to be attached
import Component, { ComponentEvent } from "@egjs/component";
class Some extends Component<{
hi: ComponentEvent;
}> {
hi() {
alert("hi");
}
thing() {
this.once("hi", this.hi);
}
}
var some = new Some();
some.thing();
some.trigger(new ComponentEvent("hi"));
// fire alert("hi");
some.trigger(new ComponentEvent("hi"));
// Nothing happens

hasOn#

Checks whether an event has been attached to a component.

Returns: boolean

  • Indicates whether the event is attached.
PARAMETERTYPEOPTIONALDEFAULTDESCRIPTION
eventNamestringThe name of the event to be attached
import Component from "@egjs/component";
class Some extends Component<{
hi: void;
}> {
some() {
this.hasOn("hi");// check hi event.
}
}

on#

Attaches an event to a component.

Returns: this

  • An instance of a component itself
PARAMETERTYPEOPTIONALDEFAULTDESCRIPTION
eventNamestring | $ts:...The name of the event to be attached or an event name - event handler mapped object.
handlerToAttachfunction | $ts:...✔️The handler function of the event to be attached
import Component, { ComponentEvent } from "@egjs/component";
class Some extends Component<{
hi: void;
}> {
hi() {
console.log("hi");
}
some() {
this.on("hi",this.hi); //attach event
}
}

off#

Detaches an event from the component.
If the eventName is not given this will detach all event handlers attached.
If the handlerToDetach is not given, this will detach all event handlers for eventName.

Returns: this

  • An instance of a component itself
PARAMETERTYPEOPTIONALDEFAULTDESCRIPTION
eventNamestring | $ts:...✔️The name of the event to be detached
handlerToDetachfunction | $ts:...✔️The handler function of the event to be detached
import Component, { ComponentEvent } from "@egjs/component";
class Some extends Component<{
hi: void;
}> {
hi() {
console.log("hi");
}
some() {
this.off("hi",this.hi); //detach event
}
}