Trailing Commas

A website promoting the use of trailing commas.

Trailing Commas

This website was made to show the benefits of using trailing commas!

What is a Trailing?

A trailing comma is when you use a comma at the end of the last line of an object or array when programming. Sometimes it is called a “final comma.” Trailing commas have always been allowed in JavaScript.

Trailing comma example.

Why should I use trailing commas?

  1. Cleaner git diffs in code merges. Also makes reading pull requests easy.
  2. Transpilers like Babel will remove trailing commas in the transpiled code, which means no problems in older browsers.
  3. You don’t have to add more commas when you add more code! Frustrated with going up a line after adding a new element, save your future-self the trouble by adding it ahead of time.

Here is a merge with a trailing comma:

Merge with trailing comma example.

Here is the same merge without a trailing comma:

Merge without trailing comma example.

As you can see, it’s much easier to read the merge when using trailing commas.