Add Dijkstra's algorithm to Typescript (#291)

09_dijkstras_algorithm/ts/iterable_graph.ts

@@ -0,0 +1,26 @@
+export interface Graph<T> {
+  [key: string]: T;
+}
+
+export class GraphIterable<T> implements Iterable<string> {
+  private graph: Graph<T>;
+
+  constructor(graph: Graph<T>) {
+    this.graph = graph;
+  }
+
+  [Symbol.iterator](): Iterator<string> {
+    const keys = Object.keys(this.graph);
+    let index = 0;
+
+    return {
+      next: (): IteratorResult<string> => {
+        if (index < keys.length) {
+          return { value: keys[index++], done: false };
+        } else {
+          return { value: undefined, done: true };
+        }
+      },
+    };
+  }
+}