```js
// Underscore's each function (roughly)
var each = function(obj, iterator, context) {
  if (obj == null) return;
  if (Array.prototype.forEach && obj.forEach === Array.prototype.forEach) {
    obj.forEach(iterator, context);
  } else if (obj.length === +obj.length) {
    for (var i = 0, l = obj.length; i < l; i++)
      iterator.call(context, obj[i], i, obj);
  }
};

each([1, 2, 3, 4], function(n) {
  n; //: number
  this; //: Date
}, new Date);

each([{x: 10}], function(o) {
  o; //: {x}
  this; //: String
}, new String("x"));
```
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]
```
```ctags
each	__DIR__/generic_each.js	/each/;"	f	lineno:2	type:void function(Array[number]|[each.!0.<i>], fn(n: number)
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iterator	__DIR__/generic_each.js	/iterator/;"	f	lineno:2	namespace:each	type:void function(each.!0.<i>)
obj	__DIR__/generic_each.js	/obj/;"	v	lineno:2	namespace:each	type:[each.!0.<i>]
i	__DIR__/generic_each.js	/i/;"	v	lineno:7	namespace:each	type:number
l	__DIR__/generic_each.js	/l/;"	v	lineno:7	namespace:each	type:number
```