JavaScriptArrays
Array.
Joins the array’s elements into a single string with a chosen separator.
- Returns
- A string made up of the array’s elements.
- Changes the original
- No
Example
#JavaScript
const tags = ['html', 'css', 'javascript']
console.log(tags.join())
console.log(tags.join(', '))
console.log(tags.join(' · '))
console.log(['2026', '09', '28'].join('-'))Console
html,css,javascript
html, css, javascript
html · css · javascript
2026-09-28
Definition and usage
#The join() method turns every array element into text and glues them into one string. By default it separates them with a comma, but you can give any separator, including an empty string.
null and undefined values turn into empty strings, and nested arrays turn into comma-separated text.
It often pairs with split(): split() breaks a string into an array, join() glues an array back into a string.
Syntax
#Syntax
array.join()
array.join(separator)Parameters
#separator
optional
The text inserted between elements. A comma by default.
Browser support
#Widely available
Works in all modern browsers, phones included. You can use it without worry.
- Chrome
- Edge
- Firefox
- Safari
Good practices
#- To build a natural list in a sentence ("HTML, CSS, and JS"),
Intl.ListFormatworks better. - When building HTML from an array, remember
join(""); otherwise, commas will show up between the elements.
Related entries
#- String.prototype.split()Splits a string into an array of pieces based on a separator: a character, a string, or a regular expression.
- Array.prototype.reverse()Reverses the order of the array’s elements in place.
- Array.prototype.map()Creates a new array with the results of calling a function for every element.
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