feat(totalIntegers): create exercise

15_totalIntegers/README.md

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+# Exercise 15 - totalIntegers
+
+Write a function that takes in an arbitrarily deep array or object and returns the total number of integers stored inside this array or object.
+
+```javascript
+totalIntegers([[[5], 3], 0, 2, ['foo'], [], [4, [5, 6]]]); // returns 7
+totalIntegers({ a: 1, b: { a: [5, 10], b: 11 } }); // returns 4
+```

15_totalIntegers/solution/totalIntegers-solution.js

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+// We could define this helper function inside of totalIntegers however that would not be best practice as everytime that the recursive totalIntegers is run it would re-create the isObject function when it could just re-use it.
+const isObject = (value) => typeof value === 'object' && value !== null;
+
+const totalIntegers = function (obj) {
+  let count = 0;
+
+  if (!isObject(obj)) {
+    return;
+  }
+
+  const elements = Object.values(obj);
+
+  for (const el of elements) {
+    if (Number.isInteger(el)) {
+      count++;
+    } else if (isObject(el)) {
+      count += totalIntegers(el);
+    }
+  }
+  return count;
+};
+
+// Do not edit below this line
+module.exports = totalIntegers;

15_totalIntegers/solution/totalIntegers-solution.spec.js

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+const totalIntegers = require('./totalIntegers-solution');
+
+describe('totalIntegers', () => {
+  test('Works with a simple array of numbers', () => {
+    expect(totalIntegers([1, 2, 3])).toBe(3);
+  });
+  test('Ignores non-integer values', () => {
+    expect(totalIntegers([1, 2, '3', 4])).toBe(3);
+  });
+  test('Works with simple objects', () => {
+    expect(totalIntegers({ a: 1, b: '2', c: 3 })).toBe(2);
+  });
+  test('Works with an empty nested array', () => {
+    expect(totalIntegers([[], [], []])).toBe(0);
+  });
+  test('Works with a very nested array', () => {
+    expect(totalIntegers([[[[[[[[[[[[[[4]]]]]], 246]]]]]]]])).toBe(2);
+  });
+  test('Works with negative numbers', () => {
+    expect(totalIntegers([5, 7, -7, [45, -1, -0], [4, 7, -4, -4, -4, [777777, -45674]], [-5477654]])).toBe(14);
+  });
+  test('Works with floats', () => {
+    expect(totalIntegers([5, 7.7, 7, [45, 1, 0], [4.0, 7, [7.77777, 4567.4]], [5477.654]])).toBe(7);
+  });
+  test('Only accepts arrays or objects', () => {
+    expect(totalIntegers('2')).toBe(undefined);
+    expect(totalIntegers(() => {})).toBe(undefined);
+    expect(totalIntegers(42)).toBe(undefined);
+    expect(totalIntegers(NaN)).toBe(undefined);
+  });
+  test('Works with NaN', () => {
+    expect(totalIntegers([5, NaN, [NaN, NaN, 64], 4])).toBe(3);
+  });
+  test('Works with a nested array of all kinds of things', () => {
+    expect(totalIntegers([NaN, [[{}], 555 ], '444', [], 74.0, undefined, [[() => {}], [4], Infinity, [[[], -44.0], [null, '-4'], NaN [[]], 6]], () => {}, [[], [-Infinity, ['4'], [4.7, -46.7], NaN]]])).toBe(5);
+  });
+  test('Works with arrays containing objects containing integers', () => {
+    expect(totalIntegers([4, 6, { a: 1, b: { a: [5, 10], b: 11 } }, 9])).toBe(7);
+  });
+});

15_totalIntegers/totalIntegers.js

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

15_totalIntegers/totalIntegers.spec.js

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