title: What is this syntax and clearly meaning
body: <p>I have come accross this syntax in a tutorial. Some say its not ES6 syntax. it was in a reduce function.
  I need a clear explanation. What is going on in these parentethes ?</p>
  
  <pre><code>{...curr, ...acc}
  </code></pre>
  
  <p>full code..</p>
  
  <pre><code>const endShape = _(raw)
  .filter(({key}) =&gt;!/garbage/.test(key))
  .map(({key,value})=&gt;({[key]:value}))
  .reduce((acc,curr)=&gt;({...curr, ...acc}));
  console.log(endShape);
  </code></pre>