title: Counting array in JSON object javascript
body: <p>According to <a href="https://stackoverflow.com/questions/1439969/javascript-counting-array-of-objects">this question</a>, I did not found the answer of how to count the array in this JSON object.</p>
  <pre><code>[{&quot;dataSymbol&quot;:&quot;21135103&quot;,&quot;isHoliday&quot;:false,&quot;isIPO&quot;:false,&quot;lastTradeTime&quot;:40073.49652777778,&quot;strikePrice&quot;:&quot;33.00&quot;,&quot;last&quot;:&quot;1.30&quot;,&quot;change&quot;:&quot;0.20&quot;,&quot;changePct&quot;:&quot;18.1818&quot;,&quot;lastRaw&quot;:1.3,&quot;ask&quot;:&quot;1.40&quot;,&quot;bid&quot;:&quot;1.30&quot;,&quot;lastTime&quot;:40073.49652777778,&quot;tick&quot;:0,&quot;openInterest&quot;:&quot;13.6K&quot;,&quot;volume&quot;:&quot;80311&quot;,&quot;expDate&quot;:40194,&quot;coName&quot;:&quot;AJR Jan0 33.0 C&quot;},
   {&quot;dataSymbol&quot;:&quot;21339645&quot;,&quot;isHoliday&quot;:false,&quot;isIPO&quot;:false,&quot;lastTradeTime&quot;:40073.50479166866,&quot;strikePrice&quot;:&quot;6.00&quot;,&quot;last&quot;:&quot;2.11&quot;,&quot;change&quot;:&quot;0.01&quot;,&quot;changePct&quot;:&quot;0.4762&quot;,&quot;lastRaw&quot;:2.11,&quot;ask&quot;:&quot;2.15&quot;,&quot;bid&quot;:&quot;2.10&quot;,&quot;lastTime&quot;:40073.50479166866,&quot;tick&quot;:0,&quot;openInterest&quot;:&quot;105.00&quot;,&quot;volume&quot;:&quot;62313&quot;,&quot;expDate&quot;:40285,&quot;coName&quot;:&quot;EK Apr0 6.0 C&quot;},
   {&quot;dataSymbol&quot;:&quot;13511861&quot;,&quot;isHoliday&quot;:false,&quot;isIPO&quot;:false,&quot;lastTradeTime&quot;:40073.489583333336,&quot;strikePrice&quot;:&quot;113.00&quot;,&quot;last&quot;:&quot;1.41&quot;,&quot;change&quot;:&quot;-6.34&quot;,&quot;changePct&quot;:&quot;-81.8065&quot;,&quot;lastRaw&quot;:1.41,&quot;ask&quot;:&quot;7.60&quot;,&quot;bid&quot;:&quot;7.45&quot;,&quot;lastTime&quot;:40073.489583333336,&quot;tick&quot;:0,&quot;openInterest&quot;:&quot;805.00&quot;,&quot;volume&quot;:&quot;62975&quot;,&quot;expDate&quot;:40138,&quot;coName&quot;:&quot;SPY Nov8 113.0 P&quot;},
   {&quot;dataSymbol&quot;:&quot;20718334&quot;,&quot;isHoliday&quot;:false,&quot;isIPO&quot;:false,&quot;lastTradeTime&quot;:40073.49375,&quot;strikePrice&quot;:&quot;40.00&quot;,&quot;last&quot;:&quot;1.42&quot;,&quot;change&quot;:&quot;-0.05&quot;,&quot;changePct&quot;:&quot;-3.4014&quot;,&quot;lastRaw&quot;:1.42,&quot;ask&quot;:&quot;1.46&quot;,&quot;bid&quot;:&quot;1.44&quot;,&quot;lastTime&quot;:40073.49375,&quot;tick&quot;:0,&quot;openInterest&quot;:&quot;116.1K&quot;,&quot;volume&quot;:&quot;60470&quot;,&quot;expDate&quot;:40194,&quot;coName&quot;:&quot;QQQQ Jan0 40.0 P&quot;}]
  </code></pre>
  <p>In this example the result should be 4.</p>
  <p>Any help appreciated!</p>