algorithm: logarithmic square root

Maths/SquareRootLogarithmic.js

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+/**
+ * @function squareRootLogarithmic
+ * @description
+ * Return the square root of 'num' rounded down
+ * to the nearest integer.
+ * More info: https://leetcode.com/problems/sqrtx/
+ * @param {Number} num Number whose square of root is to be found
+ * @returns {Number} Square root
+ * @see [BinarySearch](https://en.wikipedia.org/wiki/Binary_search_algorithm)
+ * @example
+ * const num1 = 4
+ * logarithmicSquareRoot(num1) // ====> 2
+ * @example
+ * const num2 = 8
+ * logarithmicSquareRoot(num1) // ====> 2
+ *
+ */
+const squareRootLogarithmic = (num) => {
+  if (typeof num !== 'number') {
+    throw new Error('Input data must be numbers')
+  }
+  let answer = 0
+  let sqrt = 0
+  let edge = num
+
+  while (sqrt <= edge) {
+    const mid = Math.trunc((sqrt + edge) / 2)
+    if (mid * mid === num) {
+      return mid
+    } else if (mid * mid < num) {
+      sqrt = mid + 1
+      answer = mid
+    } else {
+      edge = mid - 1
+    }
+  }
+
+  return answer
+}
+
+export { squareRootLogarithmic }

Maths/test/SquareRootLogarithmic.test.js

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+import { squareRootLogarithmic } from '../SquareRootLogarithmic'
+
+describe('SquareRootLogarithmic', () => {
+  test('Finding the square root of a positive integer', () => {
+    expect(squareRootLogarithmic(4)).toEqual(2)
+    expect(squareRootLogarithmic(16)).toEqual(4)
+    expect(squareRootLogarithmic(8)).toEqual(2)
+  })
+  test('Throwing an exception', () => {
+    expect(() => squareRootLogarithmic('not a number')).toThrow()
+    expect(() => squareRootLogarithmic(true)).toThrow()
+  })
+})