getobjectid.js

var getObjectId = function () {
  var nums = {}, strs = {};
  var numid = 0, strid = 0, objid = 0;
  var has = Object.prototype.hasOwnProperty;
  return function (object) {
    switch (typeof object) {
    case "object":case "function":
      if (object === null) return 0;
      if (has.call(object, "__id")) return object.__id;
      return object.__id = objid++ * 3 + 4;
    case "number":
      if (has.call(nums, object)) return nums[object];
      return nums[object] = numid++ * 3 + 5;
    case "string":
      if (has.call(strs, object)) return strs[object];
      return strs[object] = strid++ * 3 + 6;
    case "undefined":
      return 1;
    case "boolean":
      return object? 2: 3;
    default:
      throw new Error("unsupported type: " + typeof object);
    }
  };
}();

(function () {
  function error() {
    console.error.apply(console, arguments);
  }
  function eq() {
    var iseq = Array.reduce(arguments, function (a, b) {return a === b;});
    if (!iseq) error("not equal:", arguments);
  }
  function ne() {
    var isne = Array.reduce(arguments, function (a, b) {return a !== b;});
    if (!isne) error("equal:", arguments);
  }
  var a = getObjectId(0);
  var b = getObjectId(1);
  var c = getObjectId("a");
  var d = getObjectId("");
  var e = getObjectId("hasOwnProperty");
  var f = getObjectId(null);
  var g = getObjectId(undefined);
  var h = getObjectId(true);
  var i = getObjectId(false);
  var j = getObjectId(getObjectId);
  eq(a, getObjectId(0));
  eq(b, getObjectId(1));
  eq(c, getObjectId("a"));
  eq(d, getObjectId(""));
  eq(e, getObjectId("hasOwnProperty"));
  eq(f, getObjectId(null));
  eq(g, getObjectId(undefined));
  eq(h, getObjectId(true));
  eq(i, getObjectId(false));
  eq(j, getObjectId(getObjectId));
  ne(a, b, c, d, e, f, g, h, i, j);
}) // ();