Use new eslint-plugin-functional instead of tslint-immutable

src/file/table-of-contents/table-of-contents-properties.ts

@@ -98,7 +98,7 @@ export interface ITableOfContentsOptions {
      * with each doublet being a comma-separated set of style name and table of content level.
      * \t can be combined with \o.
      */
-    readonly stylesWithLevels?: StyleLevel[];
+    readonly stylesWithLevels?: readonly StyleLevel[];
 
     /**
      * \u Uses the applied paragraph outline level.

src/file/table-of-contents/table-of-contents.spec.ts

@@ -14,9 +14,7 @@ describe("Table of Contents", () => {
         });
 
         it("should construct a TOC with all the options and alias", () => {
-            const styles = new Array<StyleLevel>();
-            styles.push(new StyleLevel("SL", 1));
-            styles.push(new StyleLevel("SL", 2));
+            const styles = [new StyleLevel("SL", 1), new StyleLevel("SL", 2)];
 
             const props = {
                 captionLabel: "A",