`Array.prototype.join()`

Joins all array elements into a string separated by a delimiter.

Syntax

arr.join(separator)

Name	Type	Required	Description
`separator`	`string`	No	String placed between elements. Defaults to a comma ",".

string — A string with all elements joined; empty string if the array is empty.

console.log(['a', 'b', 'c'].join('-'));

Output

a-b-c

console.log([1, null, 2, undefined].join('|'));

Output

1||2|

null and undefined elements become empty strings. Does not mutate the array. Use `String.prototype.split` to reverse the operation.