fix: handle potential null values in app/data-structures directory

Signed-off-by: pierre santamaria <[email protected]>

Author: Pivouane

src/app/data-structures/business.data.structures.ts

@@ -128,9 +128,9 @@ export interface TrainrunSectionDto {
   trainrunId: number; // reference to the trainrun (main object)
   resourceId: number; // reference to the algined (resource - not yet implemented)
 
-  specificTrainrunSectionFrequencyId: number; // Default 0 - deprecate???
+  specificTrainrunSectionFrequencyId: number | null; // Default 0 - deprecate???
   path: PathDto; // cached - precomputed path for rendering
-  warnings: WarningDto[]; // business logic failures - warnings storage
+  warnings: WarningDto[] | null; // business logic failures - warnings storage
 }
 
 /**
@@ -183,7 +183,7 @@ export interface NodeDto {
   connectionTime: number; // aka Umsteigezeit - time used to change train in minutes
   trainrunCategoryHaltezeiten: TrainrunCategoryHaltezeit; // user can over-write the halte times
   symmetryAxis: number; // deprecate ???
-  warnings: WarningDto[]; // business logic failures - warnings storage
+  warnings: WarningDto[] | null; // business logic failures - warnings storage
 
   labelIds: number[]; // list of assigned filterable labels (identifiers: See Label, LabelDto.)
 }

src/app/data-structures/technical.data.structures.ts

@@ -101,8 +101,8 @@ export interface TimeLockDto {
   time: number; // minutes [0..60]
   consecutiveTime: number; // automatically updated after any data changes in the application
   lock: boolean; // used to stop the time propagation (forward/backward)
-  warning: WarningDto; // warning - if business logic detects an issue -> set human-readable warning
-  timeFormatter: TimeFormatter; // undefined or object - optional
+  warning: WarningDto | null; // warning - if business logic detects an issue -> set human-readable warning
+  timeFormatter: TimeFormatter | null; // undefined or object - optional
 }
 
 /**