Add code for chapter 6 in ts (#105)

06_breadth-first_search/ts/01_breadth-first_search.ts

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+interface Graph<T> {
+    [key: string]: T[]
+};
+
+function personIsSeller(name: string): boolean {
+    return name.endsWith('m');
+}
+
+const graph: Graph<string> = {};
+graph.you = ['alice', 'bob', 'claire'];
+graph.bob = ['anuj', 'peggy'];
+graph.alice = ['peggy'];
+graph.claire = ['thom', 'jonny'];
+graph.anuj = [];
+graph.peggy = [];
+graph.thom = [];
+graph.jonny = [];
+
+function search(name: string): boolean {
+    let searchQueue = graph[name];
+    // This array is how you keep track of which people you've searched before.
+    const searched = [];
+
+    while(searchQueue.length > 0) {
+        const person = searchQueue.shift();
+        // Only search this person if you haven't already searched them
+        if (!searched.includes(person)) {
+            if (personIsSeller(person)) {
+                console.log(`${person} is a mango seller!`);
+                return true;
+            } else {
+                searchQueue = searchQueue.concat(graph[person]);
+                // Marks this person as searched
+                searched.push(person);
+            }
+        }
+    }
+
+    return false;
+};
+
+search('you');

06_breadth-first_search/ts/tsconfig.json

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+{
+    "compilerOptions": {
+        "lib": [
+            "dom",
+            "es2015",
+            "es2016"
+        ]
+    }
+}