diff --git a/src/ol/render/canvas/TextBuilder.js b/src/ol/render/canvas/TextBuilder.js
index 10cf759148..89ec48de68 100644
--- a/src/ol/render/canvas/TextBuilder.js
+++ b/src/ol/render/canvas/TextBuilder.js
@@ -15,17 +15,17 @@ import TextPlacement from '../../style/TextPlacement.js';
  * @enum {number}
  */
 export const TEXT_ALIGN = {
-  left: 0,
-  end: 0,
-  center: 0.5,
-  right: 1,
-  start: 1,
-  top: 0,
-  middle: 0.5,
-  hanging: 0.2,
-  alphabetic: 0.8,
-  ideographic: 0.8,
-  bottom: 1
+  'left': 0,
+  'end': 0,
+  'center': 0.5,
+  'right': 1,
+  'start': 1,
+  'top': 0,
+  'middle': 0.5,
+  'hanging': 0.2,
+  'alphabetic': 0.8,
+  'ideographic': 0.8,
+  'bottom': 1
 };