back that will be called whenever an event is emitted under the given name </div></div></div></div></div><div class="qm-changelog-entry"><div class="qm-changelog-entry-header qm-code-font"><span class="qm-changelog-javascript-header"><span class="qm-changelog-javascript-prototype"><div class="qm-api-item-header qm-api-item-header-prototype"><span class="qm-api-javascript-header-prototype qm-api-header-details qm-code-font" id="hx.eventemitter"><span class="qm-api-javascript-prototype-name">hx.EventEmitter</