array_count_values.js

function array_count_values (array) {
  // http://kevin.vanzonneveld.net
  // +   original by: Ates Goral (http://magnetiq.com)
  // + namespaced by: Michael White (http://getsprink.com)
  // +      input by: sankai
  // +   improved by: Kevin van Zonneveld (http://kevin.vanzonneveld.net)
  // +   input by: Shingo
  // +   bugfixed by: Brett Zamir (http://brett-zamir.me)
  // *     example 1: array_count_values([ 3, 5, 3, "foo", "bar", "foo" ]);
  // *     returns 1: {3:2, 5:1, "foo":2, "bar":1}
  // *     example 2: array_count_values({ p1: 3, p2: 5, p3: 3, p4: "foo", p5: "bar", p6: "foo" });
  // *     returns 2: {3:2, 5:1, "foo":2, "bar":1}
  // *     example 3: array_count_values([ true, 4.2, 42, "fubar" ]);
  // *     returns 3: {42:1, "fubar":1}
  var tmp_arr = {},
    key = '',
    t = '';

  var __getType = function (obj) {
    // Objects are php associative arrays.
    var t = typeof obj;
    t = t.toLowerCase();
    if (t === "object") {
      t = "array";
    }
    return t;
  };

  var __countValue = function (value) {
    switch (typeof(value)) {
    case "number":
      if (Math.floor(value) !== value) {
        return;
      }
      // Fall-through
    case "string":
      if (value in this && this.hasOwnProperty(value)) {
        ++this[value];
      } else {
        this[value] = 1;
      }
    }
  };

  t = __getType(array);
  if (t === 'array') {
    for (key in array) {
      if (array.hasOwnProperty(key)) {
        __countValue.call(tmp_arr, array[key]);
      }
    }
  }
  return tmp_arr;
}