title: Get value by supplying key in JSON map variable(in JavaScript)
body: <p>How to get Value by supplying key to a JSON map variable(in JavaScript)?
  I have  <code>memberIdToNameMap</code>, which contains  key value pair. I have a <code>key</code> using which i want to get the value. How can we retreive it.</p>
  
  <p>I tried  <code>memberIdToNameMap[key]</code>,  but its returning <code>undefined</code>.</p>
  
  <p>--
  Thanks</p>