title: Unhandled Rejection .every(...) is not a function
body: <p>I am getting the following error in react 'Unhandled Rejection (TypeError): slots.every(...) is not a function' and I can't seem to solve it.</p>
  
  <pre><code>componentWillMount() {
    axios.get(API_BASE + `api/retrieveSlots`).then(response =&gt; {
      console.log("response via db: ", response.data);
      this.handleDBReponse(response.data);
    });
  }
  
  for (let day in schedule) {
    let slots = schedule[day];
    if (slots.length) slots.every(slot =&gt; slot === true)(schedule[day] = true)
  }
  </code></pre>