Avoid reading lineView.rest when it is null in mapFromLineView

codemirror · Oct 22, 2021 · 367b5e7 · 367b5e7
1 parent 67bb88e
commit 367b5e7
Showing 1 changed file with 8 additions and 6 deletions.
diff --git a/src/measurement/position_measurement.js b/src/measurement/position_measurement.js
@@ -61,12 +61,14 @@ function ensureLineHeights(cm, lineView, rect) {
 export function mapFromLineView(lineView, line, lineN) {
   if (lineView.line == line)
     return {map: lineView.measure.map, cache: lineView.measure.cache}
-  for (let i = 0; i < lineView.rest.length; i++)
-    if (lineView.rest[i] == line)
-      return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i]}
-  for (let i = 0; i < lineView.rest.length; i++)
-    if (lineNo(lineView.rest[i]) > lineN)
-      return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i], before: true}
+  if (lineView.rest) {
+    for (let i = 0; i < lineView.rest.length; i++)
+      if (lineView.rest[i] == line)
+        return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i]}
+    for (let i = 0; i < lineView.rest.length; i++)
+      if (lineNo(lineView.rest[i]) > lineN)
+        return {map: lineView.measure.maps[i], cache: lineView.measure.caches[i], before: true}
+  }
 }
 
 // Render a line into the hidden node display.externalMeasured. Used