allow javascript String and Number obj to be used as children

fixes #977

src/h.ts

@@ -42,15 +42,15 @@ export function h(sel: any, b?: any, c?: any): VNode {
     if (is.array(c)) {
       children = c;
     } else if (is.primitive(c)) {
-      text = c;
+      text = c.toString();
     } else if (c && c.sel) {
       children = [c];
     }
   } else if (b !== undefined && b !== null) {
     if (is.array(b)) {
       children = b;
     } else if (is.primitive(b)) {
-      text = b;
+      text = b.toString();
     } else if (b && b.sel) {
       children = [b];
     } else {

src/is.ts

@@ -1,4 +1,7 @@
 export const array = Array.isArray;
 export function primitive(s: any): s is string | number {
-  return typeof s === "string" || typeof s === "number";
+  return typeof s === "string" ||
+    typeof s === "number" ||
+    s instanceof String ||
+    s instanceof Number;
 }

test/unit/core.ts

@@ -86,6 +86,22 @@ describe("snabbdom", function () {
       const vnode = h("a", {}, "I am a string");
       assert.strictEqual(vnode.text, "I am a string");
     });
+    it("can create vnode with String obj content", function() {
+      var vnode = h("a", new String("b"));
+      assert.equal(vnode.text, "b");
+    });
+    it("can create vnode with props and String obj content", function() {
+      var vnode = h("a", {}, new String("b"));
+      assert.equal(vnode.text, "b");
+    });
+    it("can create vnode with array String obj content", function() {
+      var vnode = h("a", ["b", new String("c")]);
+      assert.equal(vnode.text, "bc");
+    });
+    it("can create vnode with Number obj content", function() {
+      var vnode = h("a", new Number(1));
+      assert.equal(vnode.text, "1");
+    });
     it("can create vnode with null props", function () {
       let vnode = h("a", null);
       assert.deepEqual(vnode.data, {});