feat(contains): create exercise

14_contains/README.md

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+# Exercise 14 - contains
+
+Write a function that searches for a value in a nested object. It returns true if the object contains that value.

14_contains/contains.js

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+const contains = function() {
+
+};
+
+// Do not edit below this line
+module.exports = contains;

14_contains/contains.spec.js

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+const contains = require('./contains');
+
+describe('contains', () => {
+  test('First test description', () => {
+    // Replace this comment with any other necessary code, and update the expect line as necessary
+
+    expect(contains()).toBe('');
+  });
+
+  test.skip('Second test description', () => {
+    // Replace this comment with any other necessary code, and update the expect line as necessary
+
+    expect(contains()).toBe('');
+  });
+});

14_contains/solution/contains-solution.js

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+const contains = function (initialObject, searchValue, queue = []) {
+  if (initialObject !== null) queue.push(initialObject);
+  if (initialObject === null && queue.length === 0) return false;
+  const item = queue.shift();
+  const values = Object.values(item);
+
+  // NaN === NaN evaluates to false
+  // Normally, we would have to do an explicit Number.isNaN() check to compare NaN equality
+  // However, Array.prototype.includes automatically handles this for us
+  if (values.includes(searchValue)) return true;
+
+  const nestedObjects = values.filter(
+    // typeof null === 'object' evaluates to true ¯\_(ツ)_/¯
+    (value) => typeof value === "object" && value !== null,
+  );
+
+  const newQueue = queue.concat(nestedObjects);
+
+  return contains(null, searchValue, newQueue);
+};
+
+// Do not edit below this line
+module.exports = contains;

14_contains/solution/contains-solution.spec.js

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+const contains = require("./contains-solution");
+
+describe("contains", () => {
+  const object = {
+    data: {
+      duplicate: "e",
+      stuff: {
+        thing: {
+          banana: NaN,
+          moreStuff: {
+            something: "foo",
+            answer: [42],
+          },
+        },
+      },
+      info: {
+        duplicate: "e",
+        magicNumber: 44,
+        empty: null,
+      },
+    },
+  };
+
+  test("true if the provided number is a value within the object", () => {
+    expect(contains(object, 44)).toBe(true);
+  });
+
+  test("true if the provided string is a value within the object", () => {
+    expect(contains(object, "foo")).toBe(true);
+  });
+
+  test("does not convert input string into a number when searching for a value within the object", () => {
+    expect(contains(object, "44")).toBe(false);
+  });
+
+  test("false if the provided string is not a value within the object", () => {
+    expect(contains(object, "bar")).toBe(false);
+  });
+
+  test("true if provided string is within the object, even if duplicated", () => {
+    expect(contains(object, "e")).toBe(true);
+  });
+
+  test("false if the provided value exists but is not a primitive", () => {
+    expect(contains(object, [42])).toBe(false);
+  });
+
+  test("true if NaN is a value within the object", () => {
+    expect(contains(object, NaN)).toBe(true);
+  });
+
+  test("false if the provided value exists and is null", () => {
+    expect(contains(object, null)).toBe(true);
+  });
+});