【fix】修复text-fild为表达式时报错的问题 ISVJ-9419

Author: songyumeng

Diff for: package.json

@@ -1,6 +1,6 @@
 {
   "name": "ol-mapbox-style",
-  "version": "2.11.2-5",
+  "version": "2.11.2-6",
   "description": "Create OpenLayers maps from Mapbox Style objects",
   "main": "index.js",
   "repository": {

Diff for: stylefunction.js

@@ -629,7 +629,11 @@ export default function(olLayer, glStyle, source, resolutions, spriteData, sprit
         let label;
         if ('text-field' in layout) {
           const textField = getValue(layer, 'layout', 'text-field', zoom, f);
-          label = fromTemplate(textField, properties);
+          if (typeof textField === 'object' && textField.sections && textField.sections.length === 1) {
+            label = textField.toString();
+          } else {
+            label = fromTemplate(textField, properties);
+          }
         }
         if (label && !skipLabel) {
           if (!hasImage) {