The join() method returns a new string by concatenating all of the elements in an array, separated by a specified separator.
Example
let message = ["JavaScript", "is", "fun."];
// join all elements of array using space
let joinedMessage = message.join(" ");
console.log(joinedMessage);
// Output: JavaScript is fun.
join() Syntax
The syntax of the join() method is:
arr.join(separator)
Here, arr is an array.
join() Parameters
The join() method takes in:
- separator (optional) - A string to separate each pair of adjacent elements of the array. By default, it is comma
,.
join() Return Value
- Returns a String with all the array elements joined by separator.
Notes:
- The
join()method does not change the original array. - Elements like
undefined,null, or empty array have an empty string representation.
Example: Using join() method
var info = ["Terence", 28, "Kathmandu"];
var info_str = info.join(" | ");
// join() does not change the original array
console.log(info); // [ 'Terence', 28, 'Kathmandu' ]
// join() returns the string by joining with separator
console.log(info_str); // Terence | 28 | Kathmandu
// empty argument = no separator
var collection = [3, ".", 1, 4, 1, 5, 9, 2];
console.log(collection.join("")); // 3.141592
var random = [44, "abc", undefined];
console.log(random.join(" and ")); // 44 and abc and
Output
[ 'Terence', 28, 'Kathmandu' ] Terence | 28 | Kathmandu 3.141592 44 and abc and
Here, we can see that the join() method converts all the array elements into a string and separates each element by the specified separator.
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