Array.prototype.join()

The join() method of Array instances returns a new string that is the concatenation of all elements in this array, separated by commas or a specified separator string. If the array has only one item, that item’s stringification is returned without using the separator.

The string conversions of all array elements are joined into one string. If an element is undefined or null, it is converted to an empty string instead of the string “null” or “undefined”.

The join method is accessed internally by Array.prototype.toString() with no arguments. Overriding join of an array instance will override its toString behavior as well.

Syntax example: join()