Added some unit tests for navLinkBuilder

Because I could not make jest work with any
references to SPFx, I separated the navLinkBuilder
into its own component.
Also, I set collectCoverage to false, as coverage collection is
currently broken and I see no easy way to fix this.

Two tests are ignored, since they describe the issue and are currently
failing.

samples/react-page-navigator/.node-version

@@ -0,0 +1 @@
+v14.20.0

samples/react-page-navigator/config/jest.config.json

@@ -1,4 +1,5 @@
 {
   "preset": "@voitanos/jest-preset-spfx-react16",
-  "rootDir": "../src"
+  "rootDir": "../src",
+  "collectCoverage": false
 }

samples/react-page-navigator/src/Service/NavLinkBuilder.test.ts

@@ -0,0 +1,268 @@
+import { IHierarchyEntry, navLinkBuilder } from "./NavLinkBuilder";
+
+interface IMockLink extends IHierarchyEntry<IMockLink> {
+  name: string;
+}
+
+const DEPTH_NO_COLLAPSABLE_HEADER = 0;
+const DEPTH_COLLAPSABLE_HEADER = 1;
+
+describe("The NavLinkBuilder without a preceding collapsable header", () => {
+
+  const depth = DEPTH_NO_COLLAPSABLE_HEADER;
+  const h1 = depth;
+  const h2 = h1+1;
+  const h3 = h2+1;
+  const h4 = h3+1;
+
+  it("should add a single item to an empty list", () => {
+    const lnk: IMockLink = {
+        name: "xyz",
+    };
+
+    const actual = navLinkBuilder.build([], lnk, h1, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+
+  it("should add a two items on the same level", () => {
+    const lnk1: IMockLink = {
+      name: "xyz",
+    };
+    const lnk2: IMockLink = {
+      name: "abc",
+    };
+
+    let actual = navLinkBuilder.build([], lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h1, depth);
+
+    expect(actual).toMatchSnapshot();
+  })
+
+  it("should add a two items on different levels", () => {
+    const lnk1: IMockLink = {
+      name: "xyz",
+    };
+    const lnk2: IMockLink = {
+      name: "abc",
+    };
+
+    let actual = navLinkBuilder.build([], lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h2, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+
+  it("should add a two items on the same level and two items on different levels", () => {
+    const lnk1: IMockLink = {
+      name: "xyz",
+    };
+    const lnk2: IMockLink = {
+      name: "abc",
+    };
+    const lnk11: IMockLink = {
+      name: "xyz.1",
+    };
+    const lnk21: IMockLink = {
+      name: "abc.1",
+    };
+
+    let actual = navLinkBuilder.build([], lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk11, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk21, h2, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+
+  it("should add a four items on different levels", () => {
+    const lnk1: IMockLink = {
+      name: "xyz",
+    };
+    const lnk2: IMockLink = {
+      name: "abc",
+    };
+    const lnk3: IMockLink = {
+      name: "def",
+    };
+    const lnk4: IMockLink = {
+      name: "geh",
+    };
+
+    let actual = navLinkBuilder.build([], lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk3, h3, depth);
+    actual = navLinkBuilder.build(actual, lnk4, h4, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+
+  it.skip("should not nest two h2", () => {
+    const lnk1: IMockLink = {
+      name: "h1",
+    };
+    const lnk2: IMockLink = {
+      name: "h2",
+    };
+    const lnk3: IMockLink = {
+      name: "h2",
+    };
+    const lnk4: IMockLink = {
+      name: "h3",
+    };
+
+    let actual = navLinkBuilder.build([], lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk3, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk4, h3, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+
+  it.skip("should not nest two h3", () => {
+    const lnk0: IMockLink = {
+      name: "h1",
+    };
+    const lnk1: IMockLink = {
+      name: "h1",
+    };
+    const lnk2: IMockLink = {
+      name: "h2",
+    };
+    const lnk3: IMockLink = {
+      name: "h2",
+    };
+    const lnk4: IMockLink = {
+      name: "h3",
+    };
+    const lnk5: IMockLink = {
+      name: "h3",
+    };
+    const lnk6: IMockLink = {
+      name: "h4",
+    };
+
+    let actual = navLinkBuilder.build([], lnk0, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk3, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk4, h3, depth);
+    actual = navLinkBuilder.build(actual, lnk5, h3, depth);
+    actual = navLinkBuilder.build(actual, lnk6, h4, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+});
+
+describe("The NavLinkBuilder with a collapsable header", () => {
+  let head: IMockLink;
+  const depth = DEPTH_COLLAPSABLE_HEADER;
+  const h1 = depth;
+  const h2 = h1+1;
+  const h3 = h2+1;
+  const h4 = h3+1;
+
+  beforeEach(() => {
+    head = {
+      name: "head",
+    };
+  });
+
+  it("should add a single item to the heading", () => {
+    const lnk: IMockLink = {
+      name: "xyz",
+    };
+
+    const actual = navLinkBuilder.build([ head ], lnk, h1, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+
+  it("should add a two items on the same level", () => {
+    const lnk1: IMockLink = {
+      name: "xyz",
+    };
+    const lnk2: IMockLink = {
+      name: "abc",
+    };
+
+    let actual = navLinkBuilder.build([ head ], lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h1, depth);
+
+    expect(actual).toMatchSnapshot();
+  })
+
+  it("should add a one item in a collapsable section two inside that one", () => {
+    const lnk1: IMockLink = {
+      name: "xyz",
+    };
+    const lnk2: IMockLink = {
+      name: "abc",
+    };
+    const lnk3: IMockLink = {
+      name: "def",
+    };
+
+    let actual = navLinkBuilder.build([ head ], lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk3, h2, depth);
+
+    expect(actual).toMatchSnapshot();
+  })
+
+  it("should not nest two h2", () => {
+    const lnk1: IMockLink = {
+      name: "h1",
+    };
+    const lnk2: IMockLink = {
+      name: "h2",
+    };
+    const lnk3: IMockLink = {
+      name: "h2",
+    };
+    const lnk4: IMockLink = {
+      name: "h3",
+    };
+
+    let actual = navLinkBuilder.build([ head ], lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk3, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk4, h3, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+
+  it("should not nest two h3", () => {
+    const lnk0: IMockLink = {
+      name: "h1",
+    };
+    const lnk1: IMockLink = {
+      name: "h1",
+    };
+    const lnk2: IMockLink = {
+      name: "h2",
+    };
+    const lnk3: IMockLink = {
+      name: "h2",
+    };
+    const lnk4: IMockLink = {
+      name: "h3",
+    };
+    const lnk5: IMockLink = {
+      name: "h3",
+    };
+    const lnk6: IMockLink = {
+      name: "h4",
+    };
+
+    let actual = navLinkBuilder.build([ head ], lnk0, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk1, h1, depth);
+    actual = navLinkBuilder.build(actual, lnk2, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk3, h2, depth);
+    actual = navLinkBuilder.build(actual, lnk4, h3, depth);
+    actual = navLinkBuilder.build(actual, lnk5, h3, depth);
+    actual = navLinkBuilder.build(actual, lnk6, h4, depth);
+
+    expect(actual).toMatchSnapshot();
+  });
+});

samples/react-page-navigator/src/Service/NavLinkBuilder.ts

@@ -0,0 +1,37 @@
+export interface IHierarchyEntry<T extends IHierarchyEntry<T>> {
+    links?: IHierarchyEntry<T>[];
+}
+
+export class navLinkBuilder {
+  /**
+   * Nests a new nav link within the nav links tree
+   * @param currentLinks current nav links
+   * @param newLink the new nav link to be added to the structure
+   * @param order place order of the new link
+   * @param depth sequence depth
+   * @returns navLinks
+   */
+   public static build<T extends IHierarchyEntry<T>>(currentLinks: T[], newLink: T, order: number, depth: number): T[] {
+    const lastIndex = currentLinks.length - 1;
+
+    if (lastIndex === -1) {
+      return [newLink];
+    }
+
+    const lastTopLevelLink = currentLinks[lastIndex];
+    lastTopLevelLink.links = lastTopLevelLink.links || [];
+
+    if (lastTopLevelLink.links.length === 0 || order === depth) {
+      if (order !== depth || depth !== 0) {
+        lastTopLevelLink.links.push(newLink);
+      } else {
+        currentLinks.push(newLink);
+      }
+    } else {
+      depth++;
+      currentLinks[lastIndex].links.concat(this.build(currentLinks[lastIndex].links, newLink, order, depth));
+    }
+
+    return currentLinks;
+  }
+}

samples/react-page-navigator/src/Service/SPService.ts

@@ -1,6 +1,7 @@
 import { INavLink } from 'office-ui-fabric-react/lib/Nav';
 import { WebPartContext } from '@microsoft/sp-webpart-base';
 import { SPHttpClient } from '@microsoft/sp-http';
+import { navLinkBuilder } from './NavLinkBuilder';
 
 export class SPService {
   /* Array to store all unique anchor URLs */
@@ -37,33 +38,6 @@ export class SPService {
     return anchorUrl;
   }
 
-  /**
-   * Nests a new nav link within the nav links tree
-   * @param currentLinks current nav links
-   * @param newLink the new nav link to be added to the structure
-   * @param order place order of the new link
-   * @param depth sequence depth
-   * @returns navLinks
-   */
-  public static navLinkBuilder(currentLinks: INavLink[], newLink: INavLink, order: number, depth: number): INavLink[] {
-    const lastIndex = currentLinks.length - 1;
-
-    if (lastIndex === -1) {
-      currentLinks.push(newLink);
-    } else if (currentLinks[lastIndex].links.length === 0 || order === depth) {
-      if (order !== depth || depth !== 0) {
-        currentLinks[lastIndex].links.push(newLink);
-      } else {
-        currentLinks.push(newLink);
-      }
-    } else {
-      depth++;
-      currentLinks[lastIndex].links.concat(this.navLinkBuilder(currentLinks[lastIndex].links, newLink, order, depth));
-    }
-
-    return currentLinks;
-  }
-
   /**
    * Returns the Anchor Links for Nav element
    * @param context Web part context
@@ -126,7 +100,7 @@ export class SPService {
 
             // Add link to nav element
             const newNavLink: INavLink = { name: headingValue, key: anchorUrl, url: anchorUrl, links: [], isExpanded: true };
-            anchorLinks = this.navLinkBuilder(anchorLinks, newNavLink, headingOrder, hasCollapsableHeader ? 1 : 0);
+            anchorLinks = navLinkBuilder.build<INavLink>(anchorLinks, newNavLink, headingOrder, hasCollapsableHeader ? 1 : 0);
           });
         }
       });

samples/react-page-navigator/src/Service/__snapshots__/NavLinkBuilder.test.ts.snap

@@ -0,0 +1,247 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`The NavLinkBuilder with a collapsable header should add a one item in a collapsable section two inside that one 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "links": Array [
+          Object {
+            "name": "abc",
+          },
+          Object {
+            "name": "def",
+          },
+        ],
+        "name": "xyz",
+      },
+    ],
+    "name": "head",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder with a collapsable header should add a single item to the heading 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "name": "xyz",
+      },
+    ],
+    "name": "head",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder with a collapsable header should add a two items on the same level 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "name": "xyz",
+      },
+      Object {
+        "name": "abc",
+      },
+    ],
+    "name": "head",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder with a collapsable header should not nest two h2 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "links": Array [
+          Object {
+            "name": "h2",
+          },
+          Object {
+            "links": Array [
+              Object {
+                "name": "h3",
+              },
+            ],
+            "name": "h2",
+          },
+        ],
+        "name": "h1",
+      },
+    ],
+    "name": "head",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder with a collapsable header should not nest two h3 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "name": "h1",
+      },
+      Object {
+        "links": Array [
+          Object {
+            "name": "h2",
+          },
+          Object {
+            "links": Array [
+              Object {
+                "name": "h3",
+              },
+              Object {
+                "links": Array [
+                  Object {
+                    "name": "h4",
+                  },
+                ],
+                "name": "h3",
+              },
+            ],
+            "name": "h2",
+          },
+        ],
+        "name": "h1",
+      },
+    ],
+    "name": "head",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder without a preceding collapsable header should add a four items on different levels 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "links": Array [
+          Object {
+            "links": Array [
+              Object {
+                "name": "geh",
+              },
+            ],
+            "name": "def",
+          },
+        ],
+        "name": "abc",
+      },
+    ],
+    "name": "xyz",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder without a preceding collapsable header should add a single item to an empty list 1`] = `
+Array [
+  Object {
+    "name": "xyz",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder without a preceding collapsable header should add a two items on different levels 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "name": "abc",
+      },
+    ],
+    "name": "xyz",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder without a preceding collapsable header should add a two items on the same level 1`] = `
+Array [
+  Object {
+    "links": Array [],
+    "name": "xyz",
+  },
+  Object {
+    "name": "abc",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder without a preceding collapsable header should add a two items on the same level and two items on different levels 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "name": "xyz.1",
+      },
+    ],
+    "name": "xyz",
+  },
+  Object {
+    "links": Array [
+      Object {
+        "name": "abc.1",
+      },
+    ],
+    "name": "abc",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder without a preceding collapsable header should not nest two h2 1`] = `
+Array [
+  Object {
+    "links": Array [
+      Object {
+        "links": Array [],
+        "name": "h2",
+      },
+      Object {
+        "links": Array [
+          Object {
+            "name": "h3",
+          },
+        ],
+        "name": "h2",
+      },
+    ],
+    "name": "h1",
+  },
+]
+`;
+
+exports[`The NavLinkBuilder without a preceding collapsable header should not nest two h3 1`] = `
+Array [
+  Object {
+    "links": Array [],
+    "name": "h1",
+  },
+  Object {
+    "links": Array [
+      Object {
+        "links": Array[],
+        "name": "h2",
+      },
+      Object {
+        "links": Array [
+          Object {
+            "name": "h3",
+          },
+          Object {
+            "links": Array [
+              Object {
+                "name": "h4",
+              },
+            ],
+            "name": "h3",
+          },
+        ],
+        "name": "h2",
+      },
+    ],
+    "name": "h1",
+  },
+]
+`;