title: javascript count number values repeated in a jsonArray items
body: <p>i need to count the number of occurrences of values in jsonArray items in javascript.
  consider this as my <code>jsonArray</code>:</p>
  
  <pre><code>{"name":"jack","age":23},
  {"name":"john","age":20},
  {"name":"alison","age":23},
  {"name":"steve","age":25},
  .
  .
  .
  </code></pre>
  
  <p>now for example i need to know how many times each age is repeated in this array, i want to count each value for each property, i mean i need a result like this :</p>
  
  <pre><code> name : {"jack" : 2,"james" : 10,"john" : 1,....}
  
   age : {"23":10,"20":15,"25":2,....}
  </code></pre>
  
  <p>what is the simplest way to achieve this?</p>
  
  <p>EDIT :
    my array is very big and i don't want to call count function for each value. i want a code to count each value repeat times.</p>