Ignore _site Build Directory in Eleventy

The other day I ran into a scenario with Eleventy in which having a .gitignore file without ignoring the build output directory (usually _site) caused the build to fail.

The error looked like this for me:

Unhandled rejection in promise ([object Promise]): (more in DEBUG output)
> Unexpected token =

`SyntaxError` was thrown:
    /path/to/node_modules/@11ty/eleventy/test/stubs/classfields-data.11ty.js:2
      data = {
           ^

    SyntaxError: Unexpected token =
...

Build Failure Cause

The reason this occurs is likely because Eleventy is trying to process files in the node_modules directory:

Paths listed in your project's .gitignore file are automatically ignored ...

If you do not have a .gitignore file in your project, the node_modules directory will be ignored automatically. This makes new Eleventy projects a little easier and helps developers new to Eleventy get ramped up easier too.

There's a goofy exception in here — if you have a .gitignore file and it has contents, but those contents do not include node_modules, then Eleventy will try to process files in node_modules.

The reason I came across this is because I was working in a space in which the project was inside a larger repository, where the root-level .gitignore had included node_modules, while my Eleventy project did not.

Easy Solution

The easy solution is to add node_modules to your .gitignore file:

.gitignore

node_modules/
_site/

Another Way to Solve

Having node_modules in your .gitignore file is usually the way to go — it's a best practice. But, if there's a reason you don't want to include it, there's still a way to get Eleventy to work.

The other approach is to add node_modules/ to .eleventyignore, which will automatically get picked up and ignored by Eleventy, but will still track those node_modules files with git (again, which you almost never want to do).

.eleventyignore

node_modules/