Invalid size set when map is not added to document

Parsing of an empty string with parseFloat resulted in NaN.

src/ol/PluggableMap.js

@@ -1496,9 +1496,8 @@ class PluggableMap extends BaseObject {
   updateSize() {
     const targetElement = this.getTargetElement();
 
-    if (!targetElement) {
+    let size = undefined;
-      this.setSize(undefined);
+    if (targetElement) {
-    } else {
       const computedStyle = getComputedStyle(targetElement);
       const width =
         targetElement.offsetWidth -
@@ -1512,15 +1511,18 @@ class PluggableMap extends BaseObject {
         parseFloat(computedStyle['paddingTop']) -
         parseFloat(computedStyle['paddingBottom']) -
         parseFloat(computedStyle['borderBottomWidth']);
-      if (height === 0 || width === 0) {
+      if (!isNaN(width) && !isNaN(height)) {
+        size = [width, height];
+        if (!hasArea(size)) {
           // eslint-disable-next-line
           console.warn(
             "No map visible because the map container's width or height are 0."
           );
         }
-      this.setSize([width, height]);
+      }
     }
 
+    this.setSize(size);
     this.updateViewportSize_();
   }
 

test/spec/ol/map.test.js

@@ -687,6 +687,7 @@ describe('ol.Map', function () {
   });
 
   describe('#setTarget', function () {
+    /** @type {Map|undefined} */
     let map;
 
     beforeEach(function () {
@@ -696,6 +697,12 @@ describe('ol.Map', function () {
       expect(map.handleResize_).to.be.ok();
     });
 
+    describe('map with target not attached to dom', function () {
+      it('has undefined as size with target not in document', function () {
+        expect(map.getSize()).to.be(undefined);
+      });
+    });
+
     describe('call setTarget with null', function () {
       it('unregisters the viewport resize listener', function () {
         map.setTarget(null);