Refactor the initialization of number properties of elements

The explicit check for undefined ensures that the value 0 of a
number property is taken from serialized elements.

projects/common/util/unit-interface-initializer.ts

@@ -5,8 +5,8 @@ export function initFontElement(serializedElement: UIElement): FontElement {
   return {
     fontColor: serializedElement.fontColor as string || '#000000',
     font: serializedElement.font as string || 'Roboto',
-    fontSize: serializedElement.fontSize as number || 20,
-    lineHeight: serializedElement.lineHeight as number || 120,
+    fontSize: serializedElement.fontSize !== undefined ? serializedElement.fontSize as number : 20,
+    lineHeight: serializedElement.lineHeight !== undefined ? serializedElement.lineHeight as number : 120,
     bold: serializedElement.bold !== undefined ? serializedElement.bold as boolean : false,
     italic: serializedElement.italic !== undefined ? serializedElement.italic as boolean : false,
     underline: serializedElement.underline !== undefined ? serializedElement.underline as boolean : false
@@ -20,7 +20,7 @@ export function initSurfaceElement(serializedElement: UIElement): SurfaceUIEleme
 export function initPlayerElement(serializedElement: UIElement): PlayerElement {
   return {
     autostart: serializedElement.autostart !== undefined ? serializedElement.autostart as boolean : false,
-    autostartDelay: serializedElement.autostartDelay as number || 0,
+    autostartDelay: serializedElement.autostartDelay !== undefined ? serializedElement.autostartDelay as number : 0,
     loop: serializedElement.loop !== undefined ? serializedElement.loop as boolean : false,
     startControl: serializedElement.startControl !== undefined ? serializedElement.startControl as boolean : true,
     pauseControl: serializedElement.pauseControl !== undefined ? serializedElement.pauseControl as boolean : false,
@@ -29,16 +29,16 @@ export function initPlayerElement(serializedElement: UIElement): PlayerElement {
       serializedElement.interactiveProgressbar as boolean : false,
     volumeControl: serializedElement.volumeControl !== undefined ? serializedElement.volumeControl as boolean : true,
     hintLabel: serializedElement.hintLabel as string || '',
-    hintLabelDelay: serializedElement.hintLabelDelay as number || 0,
+    hintLabelDelay: serializedElement.hintLabelDelay !== undefined ? serializedElement.hintLabelDelay as number : 0,
     uninterruptible:
       serializedElement.uninterruptible !== undefined ? serializedElement.uninterruptible as boolean : false,
     hideOtherPages:
       serializedElement.hideOtherPages !== undefined ? serializedElement.hideOtherPages as boolean : false,
     activeAfterID: serializedElement.activeAfterID as string || '',
-    minRuns: serializedElement.minRuns as number || 1,
-    maxRuns: serializedElement.maxRuns as number | null || null,
+    minRuns: serializedElement.minRuns !== undefined ? serializedElement.minRuns as number : 1,
+    maxRuns: serializedElement.maxRuns !== undefined ? serializedElement.maxRuns as number | null : null,
     showRestRuns: serializedElement.showRestRuns !== undefined ? serializedElement.showRestRuns as boolean : false,
     showRestTime: serializedElement.showRestTime !== undefined ? serializedElement.showRestTime as boolean : true,
-    playbackTime: serializedElement.playbackTime as number || 0
+    playbackTime: serializedElement.playbackTime !== undefined ? serializedElement.playbackTime as number : 0
   };
 }