@gravity-ui/graph/build/components/canvas/EventedComponent/EventedComponent.js

Modern graph editor component

import { Component } from "../../../lib/Component";
const listeners = new WeakMap();
export class EventedComponent extends Component {
    constructor() {
        super(...arguments);
        this.evented = true;
    }
    get events() {
        if (!listeners.has(this)) {
            listeners.set(this, new Map());
        }
        return listeners.get(this);
    }
    unmount() {
        listeners.delete(this);
        super.unmount();
    }
    handleEvent(_) {
        // noop
    }
    listenEvents(events, cbOrObject = this) {
        const unsubs = events.map((eventName) => {
            return this.addEventListener(eventName, cbOrObject);
        });
        return unsubs;
    }
    addEventListener(type, cbOrObject) {
        const cbs = this.events.get(type) || new Set();
        cbs.add(cbOrObject);
        this.events.set(type, cbs);
        return () => this.removeEventListener(type, cbOrObject);
    }
    removeEventListener(type, cbOrObject) {
        const cbs = this.events.get(type);
        if (cbs) {
            cbs.delete(cbOrObject);
        }
    }
    _fireEvent(cmp, event) {
        const handlers = listeners.get(cmp)?.get?.(event.type);
        handlers?.forEach((cb) => {
            if (typeof cb === "function") {
                cb(event);
            }
            else if (cb instanceof Component && "handleEvent" in cb && typeof cb.handleEvent === "function") {
                cb.handleEvent?.(event);
            }
        });
    }
    dispatchEvent(event) {
        const bubbles = event.bubbles || false;
        if (bubbles) {
            return this._dipping(this, event);
        }
        else if (this._hasListener(this, event.type)) {
            this._fireEvent(this, event);
            return false;
        }
        return false;
    }
    _dipping(startParent, event) {
        let stopPropagation = false;
        let parent = startParent;
        event.stopPropagation = () => {
            stopPropagation = true;
        };
        do {
            this._fireEvent(parent, event);
            if (stopPropagation) {
                return false;
            }
            parent = parent.getParent();
        } while (parent);
        return true;
    }
    _hasListener(comp, type) {
        return listeners.get(comp)?.has?.(type);
    }
}