feat(Node): add isPublic to node api

We are using attributes.public_ip because the documentation states that
this indicates if the node is public. Please see:

https://docs.mesosphere.com/1.11/overview/architecture/node-types/#public-agent-nodes

Closes DCOS-39331

src/js/structs/Node.d.ts

@@ -13,4 +13,5 @@ export default class Node extends Item {
   getOutput: () => any;
   sumTaskTypesByState: (state: any) => any;
   getUsedResources: () => any;
+  isPublic: () => boolean;
 }

src/js/structs/Node.js

@@ -94,6 +94,12 @@ class Node extends Item {
       }
     );
   }
+
+  isPublic() {
+    return (
+      findNestedPropertyInObject(this.get("attributes"), "public_ip") === "true"
+    );
+  }
 }
 
 module.exports = Node;

src/js/structs/__tests__/Node-test.js

@@ -155,4 +155,36 @@ describe("Node", function() {
       });
     });
   });
+
+  describe("#isPublic", function() {
+    const testCases = [
+      {
+        name: "returns true if attributes.public_ip is true",
+        expected: true,
+        value: { attributes: { public_ip: "true" } }
+      },
+      {
+        name: "returns false if attributes.public_ip is false",
+        expected: false,
+        value: { attributes: { public_ip: "false" } }
+      },
+      {
+        name: "returns false if attributes.public_ip is missing",
+        expected: false,
+        value: { attributes: {} }
+      },
+      {
+        name: "returns false if attributes is missing",
+        expected: false,
+        value: {}
+      }
+    ];
+
+    testCases.forEach(function(test) {
+      it(test.name, function() {
+        const node = new Node(test.value);
+        expect(node.isPublic()).toEqual(test.expected);
+      });
+    });
+  });
 });