title: How solve issue TypeError: strings.slice(...).reduce is not a function?
body: <p>I recently dicovered Gatsby and I want to use this template for my own website:
  <a href="https://github.com/toboko/gatsby-starter-fine" rel="nofollow noreferrer">https://github.com/toboko/gatsby-starter-fine</a></p>
  <p>When downloading it, manage to run it http://localhost:8000/ but I get this error which I can escape:</p>
  <p>TypeError: strings.slice(...).reduce is not a function</p>
  <p>I added my repository here so you can take a look too: <a href="https://github.com/melariza/gatsby-starter-fine" rel="nofollow noreferrer">https://github.com/melariza/gatsby-starter-fine</a></p>
  <p>Could you take a look and help fix it?</p>
  <p>Screenshot of the error:
  <a href="https://i.stack.imgur.com/CUj6w.png" rel="nofollow noreferrer">enter image description here</a></p>
  <p>Here's the error text:</p>
  <pre><code>TypeError: strings.slice(...).reduce is not a function
  css
  /Users/mga/Sites/gatsby-starter-fine/.cache/loading-indicator/style.js:5
    2 | 
    3 | function css(strings, ...keys) {
    4 |   const lastIndex = strings.length - 1
  &gt; 5 |   return (
    6 |     strings.slice(0, lastIndex).reduce((p, s, i) =&gt; p + s + keys[i], ``) +
    7 |     strings[lastIndex]
    8 |   )
  View compiled
  Style
  /Users/mga/Sites/gatsby-starter-fine/.cache/loading-indicator/style.js:14
    11 | const Style = () =&gt; (
    12 |   &lt;style
    13 |     dangerouslySetInnerHTML={{
  &gt; 14 |       __html: css`
    15 |         :host {
    16 |           --purple-60: #663399;
    17 |           --gatsby: var(--purple-60);
  View compiled
  ▶ 18 stack frames were collapsed.
  (anonymous function)
  /Users/mga/Sites/gatsby-starter-fine/.cache/app.js:165
    162 |   dismissLoadingIndicator()
    163 | }
    164 | 
  &gt; 165 | renderer(&lt;Root /&gt;, rootElement, () =&gt; {
    166 |   apiRunner(`onInitialClientRender`)
    167 | 
    168 |   // Render query on demand overlay
  View compiled
  </code></pre>