avocado-old/packages/topdown/traits/layered.trait.js

import {Trait} from '@avocado/entity';

export class Layered extends Trait {

  static type() {
    return 'layered';
  }

  constructor(entity, params, state) {
    super(entity, params, state);
    this._layer = undefined;
  }

  destroy() {
    delete this._layer;
    this.entity.emit('removedFromLayer');
  }

  get layer() {
    return this._layer;
  }

  set layer(layer) {
    this._layer = layer;
    this.entity.emit('addedToLayer');
  }

}