Merge pull request #53 from fecorreiabr/links

Add method to find link by its id

Author: anvaka

index.d.ts

@@ -120,6 +120,11 @@ declare module "ngraph.graph" {
          */
         getLink: (fromNodeId: NodeId, toNodeId: NodeId) => Link<LinkData> | undefined
 
+        /**
+         * Returns a link by its id
+         */
+        getLinkById: (linkId: LinkId) => Link<LinkData> | undefined;
+
         /**
          * Checks if link is present in the graph 
          */

index.js

@@ -246,7 +246,16 @@ function createGraph(options) {
      *
      * @returns link if there is one; undefined otherwise.
      */
-    getLink: getLink
+    getLink: getLink,
+
+    /**
+     * Gets a link by its id.
+     *
+     * @param {string} linkId link identifier
+     *
+     * @returns link if there is one; undefined otherwise.
+     */
+    getLinkById: getLinkById
   };
 
   // this will add `on()` and `fire()` methods.
@@ -445,6 +454,11 @@ function createGraph(options) {
     return links.get(makeLinkId(fromNodeId, toNodeId));
   }
 
+  function getLinkById(linkId) {
+    if (linkId === undefined) return undefined;
+    return links.get(linkId);
+  }
+
   function clear() {
     enterModification();
     forEachNode(function (node) {

test/construction.js

@@ -45,6 +45,13 @@ test('hasLink is the same as getLink', function () {
   expect(graph.getLink).toBe(graph.hasLink);
 });
 
+test('getLinkById gets link by id', function () {
+  var graph = createGraph();
+  var link = graph.addLink(1, 2);
+  var fetchedLink = graph.getLinkById(link.id);
+  expect(fetchedLink).toBe(link);
+});
+
 test('it considers uniqueLinkId as multigraph', function () {
   var options = {uniqueLinkId: true};
   createGraph(options);