Javascript Array - join() Method

Tutorialsrack 09/10/2022 Jquery Javascript

In this article, you will learn about the javascript Array built-in method Array.prototype.join(). How does this method work in javascript? 

Array.prototype.join()

This Array.prototype.join() method joins the elements of an array and returns a new string separated by commas or a specified separator string. If the length of the array is 0, then it will return the empty string.

array.join(seperator);

This method takes 1 parameter as given below:

• separator(Optional): The separator to be used. The default separator is a comma (,).

The join() method does not change the original array.

Here are some examples of Array.prototype.join() method:

//Here some examples of Array.join() Method


const arr = ['Java', 'C#', 'Python', 'SQL Server'];
console.log(arr.join());
// Output => "Java,C#,Python,SQL Server"

console.log(arr.join(', '));
// Output => "Java, C#, Python, SQL Server"

console.log(arr.join(' + '));
// Output => "Java + C# + Python + SQL Server"

console.log(arr.join(''));
// Output => "JavaC#PythonSQL Server"


//Using join() on sparse arrays
const arr1 = ['Java', , 'C#', 'Python', undefined, 'SQL Server', null];
console.log(arr1.join());
// Output => "Java,,C#,Python,,SQL Server,"

I hope this article will help you to understand the javascript Array built-in method Array.prototype.join(). 

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