@gravity-ui/graph/build/utils/Emitter.js

Modern graph editor component

import { noop } from "./functions";
const TIME_PER_FRAME_FOR_GC = 5; // 5 mc
const globalObject = typeof window === "undefined" ? global : window;
const rIC = globalObject.requestIdleCallback || globalObject.setTimeout;
const getTime = () => performance.now();
class FnWrapper {
    constructor(fn, once) {
        this.fn = fn;
        this.once = once;
        this.canBeDeleted = false;
    }
    run(...args) {
        this.fn.apply(null, Array.from(args));
        if (this.once) {
            this.destroy();
        }
    }
    destroy() {
        this.fn = noop;
        this.canBeDeleted = true;
    }
}
export class Emitter {
    constructor() {
        this.eventsForGC = new Set();
        this.eventsForGC = new Set();
        this.mapEventToFnWrapper = new Map();
        this.mapEventToMapFnToFnWrapper = new Map();
    }
    on(event, fn) {
        this._on(event, fn, false);
        return this;
    }
    once(event, fn) {
        this._on(event, fn, true);
        return this;
    }
    off(event, fn) {
        if (event === undefined) {
            this.eventsForGC = new Set();
            this.mapEventToFnWrapper = new Map();
            this.mapEventToMapFnToFnWrapper = new Map();
            return this;
        }
        if (this.mapEventToMapFnToFnWrapper?.has(event)) {
            if (typeof fn === "function" && this.mapEventToMapFnToFnWrapper.get(event)?.has(fn)) {
                this.mapEventToMapFnToFnWrapper.get(event)?.get(fn)?.destroy();
                this.eventsForGC?.add(event);
                this._launchGC();
            }
            if (fn === undefined) {
                const fnWrappers = this.mapEventToFnWrapper?.get(event) ?? [];
                for (let i = 0; i < fnWrappers.length; i += 1) {
                    fnWrappers[i].destroy();
                }
                this.eventsForGC?.add(event);
                this._launchGC();
            }
        }
        return this;
    }
    emit(event, ...args) {
        if (!this.mapEventToFnWrapper?.has(event))
            return this;
        const fnWrappers = this.mapEventToFnWrapper.get(event) ?? [];
        for (let i = 0; i < fnWrappers.length; i += 1) {
            fnWrappers[i].run(...args);
        }
        return this;
    }
    destroy() {
        this.eventsForGC = new Set();
        this.mapEventToFnWrapper = new Map();
        this.mapEventToMapFnToFnWrapper = new Map();
    }
    _on(event, fn, once) {
        if (!this.mapEventToFnWrapper?.has(event)) {
            this.mapEventToFnWrapper?.set(event, []);
            this.mapEventToMapFnToFnWrapper?.set(event, new WeakMap());
        }
        const fnWrapper = new FnWrapper(fn, Boolean(once));
        this.mapEventToFnWrapper?.get(event)?.push(fnWrapper);
        this.mapEventToMapFnToFnWrapper?.get(event)?.set(fn, fnWrapper);
    }
    _launchGC() {
        if (this.gcLaunched)
            return;
        this.gcLaunched = true;
        rIC(() => {
            this.gcLaunched = false;
            this._walkGC();
        });
    }
    _walkGC() {
        const startTime = getTime();
        for (const event of this.eventsForGC ?? []) {
            const newFnWrappers = [];
            const fnWrappers = this.mapEventToFnWrapper?.get(event) ?? [];
            for (let i = 0; i < fnWrappers.length; i += 1) {
                if (!fnWrappers[i].canBeDeleted) {
                    newFnWrappers.push(fnWrappers[i]);
                }
            }
            this.mapEventToFnWrapper?.set(event, newFnWrappers);
            this.eventsForGC?.delete(event);
            if (getTime() - startTime >= TIME_PER_FRAME_FOR_GC) {
                this._launchGC();
                return;
            }
        }
    }
}