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 (object, searchValue) {
+ const values = Object.values(object);
+
+ // 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
+ );
+
+ return nestedObjects.some((nestedObject) =>
+ contains(nestedObject, searchValue)
+ );
+};
+
+// 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);
+ });
+});