diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..2ec8a01
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,15 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+charset = utf-8
+
+[*.{js,json}]
+indent_size = 4
+trim_trailing_whitespace = true
+
+[*.md]
+indent_size = 4
+trim_trailing_whitespace = false
diff --git a/docs/.editorconfig b/docs/.editorconfig
new file mode 100644
index 0000000..52d3f50
--- /dev/null
+++ b/docs/.editorconfig
@@ -0,0 +1,6 @@
+# Unset rules for `.js` files in this directory, since they might come from
+# external sources and therefore shouldn't be affected by this repos
+# `.editorconfig`.
+[*.js]
+indent_size = unset
+trim_trailing_whitespace = unset
diff --git a/src/extension.js b/src/extension.js
index 4d37617..3067cf0 100644
--- a/src/extension.js
+++ b/src/extension.js
@@ -89,7 +89,7 @@ class Extension {
         const validLeftBoxOrder = this._createValidBoxOrder("left");
         const validCenterBoxOrder = this._createValidBoxOrder("center");
         const validRightBoxOrder = this._createValidBoxOrder("right");
-        
+
         // Go through the items (or rather their roles) of a box and order the
         // box accordingly.
         const orderBox = (boxOrder, box) => {