Accept undefined from childrenFn

jessitron · Jan 20, 2019 · 4985c12 · 4985c12
1 parent fe0ea57
commit 4985c12
Show file tree

Hide file tree

Showing 7 changed files with 24 additions and 5 deletions.
diff --git a/index.d.ts.map b/index.d.ts.map
diff --git a/index.js b/index.js
diff --git a/index.js.map b/index.js.map
diff --git a/index.ts b/index.ts
@@ -18,7 +18,8 @@ export function stringifyTree<T>(tn: T, nameFn: (t: T) => string, childrenFn: (t
         });
     }
     function nodeToStrings(tn: T): string[] {
-        const children = [...childrenFn(tn)]; // copy the array
+        const origChildren = childrenFn(tn) || [];
+        const children = [...origChildren]; // copy the array
         if (children.length === 0) {
             return ["─ " + nameFn(tn)];
         }

diff --git a/test/stringifyTree.test.js b/test/stringifyTree.test.js
diff --git a/test/stringifyTree.test.js.map b/test/stringifyTree.test.js.map
diff --git a/test/stringifyTree.test.ts b/test/stringifyTree.test.ts
@@ -10,6 +10,15 @@ describe("stringify", () => {
         console.log("tree:\n" + result);
         assert.deepEqual(result, "─ hi");
     });
+    it("treats undefined as empty children", () => {
+        type TN = { name: string, children: TN[] }
+        const tree = {
+            name: "hi", children: undefined,
+        } as unknown as TN;
+        const result = stringifyTree(tree, t => t.name, t => t.children);
+        console.log("tree:\n" + result);
+        assert.deepEqual(result, "─ hi");
+    });
     it("prints a tree with a child", () => {
         const tree = {
             name: "hi", children: [