# Get changed files in a git repository with Node.js

> This snippet will help you retrieve the list of the currently changed files in a git repository using Node.js.

*Published: 2022-12-26*
*Canonical: https://makerkit.dev/blog/tutorials/staged-git-files-nodejs*

---

It can be useful to retrieve the list of the currently changed files in a
git repository.

For example, you might want to run a script only if a
specific file has been changed, such as when indexing a search engine with
new content that has been added to a repository: we use this technique in
this website when a new post is added or an existing one is updated.

To write the script, we will use:
1. the `git diff` command
2. and Node.js

```ts
import { execSync } from 'child_process';

function getChangedFiles(extension: string = '') {
  const extensionFilter = extension ? `-- '***.${extension}'` : '';
  const command = `git diff HEAD^ HEAD --name-only ${extensionFilter}`;
  const diffOutput = execSync().toString(command);

  return diffOutput.toString().split('\n').filter(Boolean);
}
```

The `getChangedFiles` function takes an optional `extension` parameter that
will filter out the files that do not have the given extension.

For example, if we want to retrieve the list of the changed files that have a
`.mdx` extension, we can call the function like this:

```ts
const changedFiles = getChangedFiles('mdx');
```

The `getChangedFiles` function will return an array of the changed files
whose path starts from the current directory.

That's it! Hope you found this snippet useful. Ciao!