Center should remain valid when resolution is not set

src/ol/centerconstraint.js

@@ -18,14 +18,19 @@ export function createExtent(extent, onlyCenter, smooth) {
   return (
     /**
      * @param {import("./coordinate.js").Coordinate|undefined} center Center.
-     * @param {number} resolution Resolution.
+     * @param {number|undefined} resolution Resolution.
      * @param {import("./size.js").Size} size Viewport size; unused if `onlyCenter` was specified.
      * @param {boolean} [opt_isMoving] True if an interaction or animation is in progress.
      * @param {Array<number>} [opt_centerShift] Shift between map center and viewport center.
      * @return {import("./coordinate.js").Coordinate|undefined} Center.
      */
     function (center, resolution, size, opt_isMoving, opt_centerShift) {
-      if (center) {
+      if (!center) {
+        return undefined;
+      }
+      if (!resolution && !onlyCenter) {
+        return center;
+      }
       const viewWidth = onlyCenter ? 0 : size[0] * resolution;
       const viewHeight = onlyCenter ? 0 : size[1] * resolution;
       const shiftX = opt_centerShift ? opt_centerShift[0] : 0;
@@ -48,10 +53,10 @@ export function createExtent(extent, onlyCenter, smooth) {
 
       let x = clamp(center[0], minX, maxX);
       let y = clamp(center[1], minY, maxY);
-        const ratio = 30 * resolution;
 
       // during an interaction, allow some overscroll
-        if (opt_isMoving && smooth) {
+      if (opt_isMoving && smooth && resolution) {
+        const ratio = 30 * resolution;
         x +=
           -ratio * Math.log(1 + Math.max(0, minX - center[0]) / ratio) +
           ratio * Math.log(1 + Math.max(0, center[0] - maxX) / ratio);
@@ -61,9 +66,6 @@ export function createExtent(extent, onlyCenter, smooth) {
       }
 
       return [x, y];
-      } else {
-        return undefined;
-      }
     }
   );
 }