Upgrade to TS 5.6.

Mainly implements a workaround for error TS2855 that prevents accessing parent class
fields as `super.field` [introduced in TS
5.3](https://www.typescriptlang.org/docs/handbook/release-notes/typescript-5-3.html#checks-for-super-property-accesses-on-instance-fields). In
valid JS, super can only be used to access get/set accessors or methods from
parent classes that are declared on the prototype, but not instance
fields (declared as `x = "something"`). In our case though, traits are declared
as getters and not fields, however because we use mapped types to mixin the
traits into a class and mapped types does not allow specifying getter/setter
variants, TS considers our traits to be fields and raises TS2855.

The workaround in this PR defines these erroring traits as getters which seems
to convince TS (at least for now) that they are valid accessors eventhough they
still are typed using mapped.

Hopefully in the future, we get this TS feature implementing [variant accessors
for mapped types](microsoft/TypeScript#43826), then
we can get rid of this workaround.

lib/Map/Region/RegionProvider.ts

@@ -447,8 +447,8 @@ export default class RegionProvider {
       if (!isDefined(disambigCode)) {
         // we have an ambiguous value, but nothing with which to disambiguate. We pick the first, warn.
         console.warn(
-          "Ambiguous value found in region mapping: " + codeAfterReplacement ??
-            code
+          "Ambiguous value found in region mapping: " +
+            (codeAfterReplacement || code)
         );
         return ids[0];
       }

lib/ModelMixins/GeojsonMixin.ts

@@ -31,10 +31,10 @@ import {
 } from "mobx";
 import { createTransformer } from "mobx-utils";
 import {
-  Feature as ProtomapsFeature,
   GeomType,
   LineSymbolizer,
-  PolygonSymbolizer
+  PolygonSymbolizer,
+  Feature as ProtomapsFeature
 } from "protomaps";
 import Cartesian2 from "terriajs-cesium/Source/Core/Cartesian2";
 import Cartesian3 from "terriajs-cesium/Source/Core/Cartesian3";
@@ -77,8 +77,8 @@ import { isJson } from "../Core/loadBlob";
 import StandardCssColors from "../Core/StandardCssColors";
 import TerriaError, { networkRequestError } from "../Core/TerriaError";
 import ProtomapsImageryProvider, {
-  GeojsonSource,
   GEOJSON_SOURCE_LAYER_NAME,
+  GeojsonSource,
   ProtomapsData
 } from "../Map/ImageryProvider/ProtomapsImageryProvider";
 import Reproject from "../Map/Vector/Reproject";
@@ -1491,7 +1491,7 @@ export function toFeatureCollection(
   }
   if (Array.isArray(json) && json.every((item) => isGeometries(item))) {
     return featureCollection(
-      json.map((item) => feature(item, item.properties))
+      json.map((item) => feature(item))
     ) as FeatureCollectionWithCrs;
   }
 }

lib/Models/Catalog/CatalogItems/OpenDataSoftCatalogItem.ts

@@ -631,8 +631,8 @@ export default class OpenDataSoftCatalogItem
           ([field, value]) => {
             // geoPoint2dFieldName will return a JSON object - spilt lat/lon columns
             if (field === this.geoPoint2dFieldName && isJsonObject(value)) {
-              cols.lat[index] = `${value.lat}` ?? "";
-              cols.lon[index] = `${value.lon}` ?? "";
+              cols.lat[index] = `${value.lat}`;
+              cols.lon[index] = `${value.lon}`;
             } else {
               // Copy current field into columns object
               if (!Array.isArray(cols[field])) {

lib/Traits/TraitsClasses/CatalogMemberTraits.ts

@@ -107,15 +107,19 @@ class CatalogMemberTraits extends ModelTraits {
     name: "Name",
     description: "The name of the catalog item."
   })
-  name?: string;
+  get name(): string | undefined {
+    return;
+  }
 
   @primitiveTrait({
     type: "string",
     name: "Description",
     description:
       "The description of the catalog item. Markdown and HTML may be used."
   })
-  description?: string;
+  get description(): string | undefined {
+    return;
+  }
 
   @primitiveTrait({
     type: "boolean",
@@ -131,7 +135,9 @@ class CatalogMemberTraits extends ModelTraits {
     description:
       "The name of the item to be displayed in the catalog, if it is different from the one to display in the workbench."
   })
-  nameInCatalog?: string;
+  get nameInCatalog(): string | undefined {
+    return;
+  }
 
   @objectArrayTrait({
     type: InfoSectionTraits,
@@ -174,7 +180,9 @@ class CatalogMemberTraits extends ModelTraits {
     name: "Short report",
     description: "A short report to show on the now viewing tab."
   })
-  shortReport?: string;
+  get shortReport(): string | undefined {
+    return;
+  }
 
   @objectArrayTrait({
     type: ShortReportTraits,
@@ -238,7 +246,9 @@ class CatalogMemberTraits extends ModelTraits {
     name: "Disable about data",
     description: "Disables the 'About Data' button in the workbench."
   })
-  disableAboutData?: boolean;
+  get disableAboutData(): boolean | undefined {
+    return;
+  }
 
   @primitiveTrait({
     type: "boolean",
@@ -249,14 +259,14 @@ class CatalogMemberTraits extends ModelTraits {
   shareable: boolean = true;
 }
 
-/* eslint-disable-next-line @typescript-eslint/no-unsafe-declaration-merging */
+// /* eslint-disable-next-line @typescript-eslint/no-unsafe-declaration-merging */
 interface CatalogMemberTraits {
   // Add traits here that you want to override from some Mixin or Model class
   // without generating TS2611 type error.
-  name?: CatalogMemberTraits["name"];
-  shortReport?: CatalogMemberTraits["shortReport"];
-  description?: CatalogMemberTraits["description"];
-  disableAboutData?: CatalogMemberTraits["disableAboutData"];
+  name: CatalogMemberTraits["name"];
+  shortReport: CatalogMemberTraits["shortReport"];
+  description: CatalogMemberTraits["description"];
+  disableAboutData: CatalogMemberTraits["disableAboutData"];
 }
 
 export default CatalogMemberTraits;

lib/Traits/TraitsClasses/GetCapabilitiesTraits.ts

@@ -8,7 +8,9 @@ export default class GetCapabilitiesTraits extends ModelTraits {
     description:
       "The URL at which to access to the OGC GetCapabilities service."
   })
-  getCapabilitiesUrl?: string;
+  get getCapabilitiesUrl(): string | undefined {
+    return;
+  }
 
   @primitiveTrait({
     type: "string",

lib/Traits/TraitsClasses/HighlightColorTraits.ts

@@ -8,5 +8,7 @@ export default class HighlightColorTraits extends ModelTraits {
     description:
       "The color used to highlight a feature when it is picked. If not set, this defaults to `Terria.baseMapContrastColor`"
   })
-  highlightColor?: string;
+  get highlightColor(): string | undefined {
+    return;
+  }
 }

lib/Traits/TraitsClasses/MappableTraits.ts

@@ -230,7 +230,9 @@ class MappableTraits extends mixTraits(AttributionTraits) {
     description:
       "Disables the zoom to (aka 'Ideal Zoom') button in the workbench."
   })
-  disableZoomTo: boolean = false;
+  get disableZoomTo(): boolean {
+    return false;
+  }
 
   @primitiveTrait({
     type: "boolean",
@@ -281,7 +283,7 @@ class MappableTraits extends mixTraits(AttributionTraits) {
   maximumShownFeatureInfos?: number;
 }
 
-/* eslint-disable-next-line @typescript-eslint/no-unsafe-declaration-merging */
+// /* eslint-disable-next-line @typescript-eslint/no-unsafe-declaration-merging */
 interface MappableTraits {
   // Add traits here that you want to override from some Mixin or Model class
   // without generating TS2611 type error.

lib/Traits/TraitsClasses/SensorObservationCatalogItemTraits.ts

@@ -166,5 +166,7 @@ export default class SensorObservationCatalogItemTraits extends mixTraits(
     type: "string",
     description: "The identifier of the selected observable property"
   })
-  selectedObservableId?: string;
+  get selectedObservableId(): string | undefined {
+    return;
+  }
 }

lib/Traits/TraitsClasses/TimeVaryingTraits.ts

@@ -16,7 +16,9 @@ export default class TimeVaryingTraits extends mixTraits(CatalogMemberTraits) {
     type: "string",
     isNullable: true
   })
-  currentTime?: string | null;
+  get currentTime(): string | null | undefined {
+    return;
+  }
 
   @primitiveTrait({
     name: "Initial Time Source",
@@ -37,23 +39,29 @@ export default class TimeVaryingTraits extends mixTraits(CatalogMemberTraits) {
       "The earliest time for which this dataset is available. This will be the start of the range shown on the timeline control.",
     type: "string"
   })
-  startTime?: string;
+  get startTime(): string | undefined {
+    return;
+  }
 
   @primitiveTrait({
     name: "Stop Time",
     description:
       "The latest time for which this dataset is available. This will be the end of the range shown on the timeline control.",
     type: "string"
   })
-  stopTime?: string;
+  get stopTime(): string | undefined {
+    return;
+  }
 
   @primitiveTrait({
     name: "Time Multiplier",
     description:
       "The multiplier to use in progressing time for this dataset. For example, `5.0` means that five seconds of dataset time will pass for each one second of real time.",
     type: "number"
   })
-  multiplier?: number;
+  get multiplier(): number | undefined {
+    return;
+  }
 
   @primitiveTrait({
     name: "Is Paused",

lib/Traits/TraitsClasses/UrlTraits.ts

@@ -8,31 +8,37 @@ class UrlTraits extends ModelTraits {
     name: "URL",
     description: "The base URL of the file or service."
   })
-  url?: string;
+  get url(): string | undefined {
+    return;
+  }
 
   @primitiveTrait({
     type: "boolean",
     name: "Force proxy",
     description: "Force the default proxy to be used for all network requests."
   })
-  forceProxy?: boolean;
+  get forceProxy(): boolean | undefined {
+    return;
+  }
 
   @primitiveTrait({
     type: "string",
     name: "Cache Duration",
     description:
       "The cache duration to use for proxied URLs for this catalog member. If undefined, proxied URLs are effectively cachable forever. The duration is expressed as a Varnish-like duration string, such as '1d' (one day) or '10000s' (ten thousand seconds)."
   })
-  cacheDuration?: string;
+  get cacheDuration(): string | undefined {
+    return;
+  }
 }
 
 /* eslint-disable-next-line @typescript-eslint/no-unsafe-declaration-merging */
 interface UrlTraits {
   // Add traits here that you want to override from some Mixin or Model class
   // without generating TS2611 type error.
-  url?: UrlTraits["url"];
-  cacheDuration?: UrlTraits["cacheDuration"];
-  forceProxy?: UrlTraits["forceProxy"];
+  url: UrlTraits["url"];
+  cacheDuration: UrlTraits["cacheDuration"];
+  forceProxy: UrlTraits["forceProxy"];
 }
 
 export default UrlTraits;

package.json

@@ -181,7 +181,7 @@
     "thredds-catalog-crawler": "0.0.7",
     "ts-essentials": "^5.0.0",
     "ts-loader": "^5.3.3",
-    "typescript": "~5.2.0",
+    "typescript": "^5.6.2",
     "urijs": "^1.18.12",
     "url-loader": "^1.1.2",
     "webpack": "~4.47.0",