@amblines/react-table-filter/src/lib/eventStack/eventStack.js

> Module creates Excel like Column Filters for Table. The filter list contains all the unique items present in every column. See image below for example.

import EventTarget from './eventTarget';
import normalizeTarget from './normalizeTarget';

class EventStack {
  constructor() {
    this._targets = new Map();
  }

  // ------------------------------------
  // Target utils
  // ------------------------------------

  _find(target, autoCreate = true) {
    const normalized = normalizeTarget(target);

    if (this._targets.has(normalized)) return this._targets.get(normalized);
    if (!autoCreate) return;

    const eventTarget = new EventTarget(normalized);
    this._targets.set(normalized, eventTarget);

    return eventTarget;
  }

  _remove(target) {
    const normalized = normalizeTarget(target);

    this._targets.delete(normalized);
  }

  sub(name, handlers, options = {}) {
    const {target = document, pool = 'default'} = options;
    const eventTarget = this._find(target);

    eventTarget.sub(name, handlers, pool);
  }

  unsub(name, handlers, options = {}) {
    const {target = document, pool = 'default'} = options;
    const eventTarget = this._find(target, false);

    if (eventTarget) {
      eventTarget.unsub(name, handlers, pool);
      if (eventTarget.empty()) this._remove(target);
    }
  }
}

const instance = new EventStack();

export default instance;