Ensure buildtime compatibility with Theia Community Release (#91)

- Updates to Typescript 4.8
- Upgrades the resolved Theia versions to the latest Release (i.e. bump in yarn.lock)
- Bumps the version of eslint and related plugins to be compatible with TS 4.8
- Fixes two compilation errors introduced by the new TS version

package.json

@@ -47,11 +47,11 @@
   "devDependencies": {
     "@types/chai": "^4.2.12",
     "@types/mocha": "^8.0.0",
-    "@typescript-eslint/eslint-plugin": "5.3.0",
-    "@typescript-eslint/parser": "5.3.0",
+    "@typescript-eslint/eslint-plugin": "5.39.0",
+    "@typescript-eslint/parser": "5.39.0",
     "chai": "^4.2.0",
-    "eslint": "^8.1.0",
-    "eslint-config-prettier": "^8.3.0",
+    "eslint": "^8.24.0",
+    "eslint-config-prettier": "^8.5.0",
     "eslint-plugin-header": "^3.1.1",
     "eslint-plugin-no-null": "^1.0.2",
     "jenkins-mocha": "^8.0.0",
@@ -60,7 +60,7 @@
     "rimraf": "^3.0.2",
     "semver": "^7.3.2",
     "ts-node": "^8.10.2",
-    "typescript": "3.9.2"
+    "typescript": "^4.8.4"
   },
   "scripts": {
     "clean": "rimraf lib artifacts",

src/sprotty/theia-sprotty-context-menu-service.ts

@@ -162,7 +162,7 @@ function getBooleanValue(value: any, defaultValue: boolean) {
 }
 
 function isFunction(value: () => boolean | boolean): value is () => boolean {
-    return !!(value && value.constructor && value.call && value.apply);
+    return !!(value && value.constructor && value.apply);
 }
 
 function isBoolean(value: () => boolean | boolean): boolean {

src/theia/diagram-widget.ts

@@ -61,6 +61,8 @@ export class DiagramWidget extends BaseWidget implements StatefulWidget, Navigat
 
     protected _modelSource: ModelSource;
 
+    readonly id: string;
+
     get uri(): URI {
         return new URI(this.options.uri);
     }
@@ -84,18 +86,15 @@ export class DiagramWidget extends BaseWidget implements StatefulWidget, Navigat
             return this.widgetId;
     }
 
-    get id(): string {
-        return this.widgetId;
-    }
-
     constructor(protected options: DiagramWidgetOptions,
-                readonly widgetId: string,
-                readonly diContainer: Container,
-                readonly connector?: TheiaSprottyConnector) {
+        readonly widgetId: string,
+        readonly diContainer: Container,
+        readonly connector?: TheiaSprottyConnector) {
         super();
         this.title.closable = true;
         this.title.label = options.label;
         this.title.iconClass = options.iconClass;
+        this.id = widgetId;
     }
 
     protected onAfterAttach(msg: Message): void {
@@ -196,7 +195,7 @@ export class DiagramWidget extends BaseWidget implements StatefulWidget, Navigat
      * after creating the widget and before activating it, we use this method to wait for the
      * SVG to be appended to the DOM.
      */
-    async getSvgElement(): Promise<HTMLElement | undefined> {
+    async getSvgElement(): Promise<HTMLElement | undefined> {
         return new Promise<HTMLElement | undefined>((resolve) => {
             let frames = 0;
             const waitForSvg = () => {