title: Inline object literal with a variable property
body: <p>Why does Javascript syntax not support inline object literals with a variable property?  For example:</p>
  
  <pre><code>const f = function (arg) {
    console.log(arg);
  }
  
  f({}['some key'] = 1) // 1
  f({ 'some key' : 1})  // [object Object] { some key: 1 }
  </code></pre>
  
  <p>Is there another alternative other than the two steps?</p>
  
  <pre><code>var o = {}
  o['some key'] = 1
  f(o)
  </code></pre>
  
  <p>Thanks!</p>