London | 26-ITP-May | Tomislav Dukez | Sprint 1 | Coursework

Sprint-1/fix/median.js

@@ -6,9 +6,25 @@
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  // Check if the input is an array
+  if (!Array.isArray(list)) {
+    return null;
+  }
+  // Filter out non-numeric values from the array
+  const numbers = list.filter((x) => typeof x === "number");
+  // If the filtered array is empty, return null
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  // Sort the numbers in ascending order so the median can be calculated correctly
+  numbers.sort((a, b) => a - b);
+
+  const middleIndex = Math.floor(numbers.length / 2);
+  // Calculate the median based on whether the length of the array is even or odd
+  return numbers.length % 2 === 0
+    ? (numbers[middleIndex - 1] + numbers[middleIndex]) / 2
+    : numbers[middleIndex];
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,12 @@
-function dedupe() {}
+function dedupe(inputArray) {
+  const uniqueElements = [];
+  for (const el of inputArray) {
+    if (uniqueElements.includes(el)) {
+      continue;
+    }
+    uniqueElements.push(el);
+  }
+  return uniqueElements;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -13,16 +13,32 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 
 // Acceptance Criteria:
 
-// Given an empty array
-// When passed to the dedupe function
-// Then it should return an empty array
-test.todo("given an empty array, it returns an empty array");
+describe("dedupe", () => {
+  // Given an empty array
+  // When passed to the dedupe function
+  // Then it should return an empty array
+  it("returns an empty array when given empty array", () => {
+    expect(dedupe([])).toStrictEqual([]);
+  });
 
-// Given an array with no duplicates
-// When passed to the dedupe function
-// Then it should return a copy of the original array
-
-// Given an array of strings or numbers
-// When passed to the dedupe function
-// Then it should return a new array with duplicates removed while preserving the 
-// first occurrence of each element from the original array.
+  // Given an array with no duplicates
+  // When passed to the dedupe function
+  // Then it should return a copy of the original array
+  it("returns a copy of the array is the one given without duplicates", () => {
+    expect(dedupe([1, 2, 3, 4])).toStrictEqual([1, 2, 3, 4]);
+    expect(dedupe(["a", "b", "c", "d"])).toStrictEqual(["a", "b", "c", "d"]);
+  });
+  // Given an array of strings or numbers
+  // When passed to the dedupe function
+  // Then it should return a new array with duplicates removed while preserving the
+  // first occurrence of each element from the original array.
+  it("returns an array of unique elements with order preserving the first occurence of each element", () => {
+    expect(dedupe(["a", "a", "a", "b", "b", "c"])).toStrictEqual([
+      "a",
+      "b",
+      "c",
+    ]);
+    expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toStrictEqual([5, 1, 2, 3, 8]);
+    expect(dedupe([1, 2, 1])).toStrictEqual([1, 2]);
+  });
+});

Sprint-1/implement/max.js

@@ -1,4 +1,17 @@
 function findMax(elements) {
+  // filter out only numbers to the new array
+  const numElements = elements.filter(
+    (el) => !isNaN(el) && typeof el === "number"
+  );
+
+  return numElements.reduce(
+    (acc, curr) => (acc > curr ? acc : curr),
+    -Infinity
+  );
 }
 
 module.exports = findMax;
+
+console.log(findMax([-10, 20, 0, 100, 1]));
+console.log(findMax([]));
+console.log(findMax(["I", 2, "am", -1000, "Lord", "200", "Voldemort", 10]));

Sprint-1/implement/max.test.js

@@ -1,43 +1,67 @@
-/* Find the maximum element of an array of numbers
+/* find the maximum element of an array of numbers
 
-In this kata, you will need to implement a function that find the largest numerical element of an array.
+in this kata, you will need to implement a function that find the largest numerical element of an array.
 
-E.g. max([30, 50, 10, 40]), target output: 50
-E.g. max(['hey', 10, 'hi', 60, 10]), target output: 60 (sum ignores any non-numerical elements)
+e.g. max([30, 50, 10, 40]), target output: 50
+e.g. max(['hey', 10, 'hi', 60, 10]), target output: 60 (sum ignores any non-numerical elements)
 
-You should implement this function in max.js, and add tests for it in this file.
+you should implement this function in max.js, and add tests for it in this file.
 
-We have set things up already so that this file can see your function from the other file.
+we have set things up already so that this file can see your function from the other file.
 */
 
 const findMax = require("./max.js");
 
-// Given an empty array
-// When passed to the max function
-// Then it should return -Infinity
-// Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+describe("findMax function", () => {
+  // given an empty array
+  // when passed to the max function
+  // then it should return -infinity
+  // delete this test.todo and replace it with a test.
+  it("given an empty array, returns -Infinity", () => {
+    expect(findMax([])).toEqual(-Infinity);
+  });
 
-// Given an array with one number
-// When passed to the max function
-// Then it should return that number
+  // given an array with one number
+  // when passed to the max function
+  // then it should return that number
+  it("given an array with one number, returns that number", () => {
+    expect(findMax([10])).toEqual(10);
+  });
 
-// Given an array with both positive and negative numbers
-// When passed to the max function
-// Then it should return the largest number overall
+  // given an array with both positive and negative numbers
+  // when passed to the max function
+  // then it should return the largest number overall
+  it("give an array with both positive and negative numbers, returns larges number overall", () => {
+    expect(findMax([-10, 20, 0, 100, 1])).toEqual(100);
+    expect(findMax([-10, -100, 0, 11, 1, -5])).toEqual(11);
+  });
 
-// Given an array with just negative numbers
-// When passed to the max function
-// Then it should return the closest one to zero
+  // given an array with just negative numbers
+  // when passed to the max function
+  // then it should return the closest one to zero
+  it("given an array with just negative numbers, returns number closest to zero", () => {
+    expect(findMax([-1, -200, -35, -4, -100])).toEqual(-1);
+  });
+  // given an array with decimal numbers
+  // when passed to the max function
+  // then it should return the largest decimal number
+  it("given an array with decimal numbers, returns largest decimal number", () => {
+    expect(findMax([-1.2, 3.14, -0.1, -0.007, 5.5, 5.50001])).toEqual(5.50001);
+  });
 
-// Given an array with decimal numbers
-// When passed to the max function
-// Then it should return the largest decimal number
+  // Given an array with non-number values
+  // When passed to the max function
+  // Then it should return the max and ignore non-numeric values
+  it("given an array with non-number values, returns max, non-numeric values ignored", () => {
+    expect(
+      findMax(["I", 2, "am", -1000, "Lord", "200", "Voldemort", 10])
+    ).toEqual(10);
+  });
 
-// Given an array with non-number values
-// When passed to the max function
-// Then it should return the max and ignore non-numeric values
-
-// Given an array with only non-number values
-// When passed to the max function
-// Then it should return the least surprising value given how it behaves for all other inputs
+  // Given an array with only non-number values
+  // When passed to the max function
+  // Then it should return the least surprising value given how it behaves for all other inputs
+  it("given an array with only non-numeric values, it returns -Infinity", () => {
+    expect(findMax(["I", "am", "Lord", "Voldemort"])).toEqual(-Infinity);
+  });
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,10 @@
 function sum(elements) {
+  return elements.reduce((acc, curr) => {
+    if (typeof curr !== "number") {
+      return acc;
+    }
+    return acc + curr;
+  }, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -7,30 +7,52 @@ E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical
 */
 
 const sum = require("./sum.js");
-
-// Acceptance Criteria:
-
-// Given an empty array
-// When passed to the sum function
-// Then it should return 0
-test.todo("given an empty array, returns 0")
-
-// Given an array with just one number
-// When passed to the sum function
-// Then it should return that number
-
-// Given an array containing negative numbers
-// When passed to the sum function
-// Then it should still return the correct total sum
-
-// Given an array with decimal/float numbers
-// When passed to the sum function
-// Then it should return the correct total sum
-
-// Given an array containing non-number values
-// When passed to the sum function
-// Then it should ignore the non-numerical values and return the sum of the numerical elements
-
-// Given an array with only non-number values
-// When passed to the sum function
-// Then it should return the least surprising value given how it behaves for all other inputs
+describe("sum function", () => {
+  // Acceptance Criteria:
+
+  // Given an empty array
+  // When passed to the sum function
+  // Then it should return 0
+  it("given an empty array, should return 0", () => {
+    expect(sum([])).toEqual(0);
+  });
+
+  // Given an array with just one number
+
+  // When passed to the sum function
+  // Then it should return that number
+  it("given an array of just one number, returns that number", () => {
+    expect(sum([2])).toEqual(2);
+  });
+  // Given an array containing negative numbers
+  // When passed to the sum function
+  // Then it should still return the correct total sum
+  it("given an array containing negative numbers, returns correct total sum", () => {
+    expect(sum([-1, -3, -5, 0])).toEqual(-9);
+  });
+  // Given an array with decimal/float numbers
+  // When passed to the sum function
+  // Then it should return the correct total sum
+  it("given an array with decimal numbers, returns correct total sum", () => {
+    expect(sum([-1.2, 2.3, 0.001, 2.0])).toEqual(3.101);
+  });
+  // Given an array containing non-number values
+  // When passed to the sum function
+  // Then it should ignore the non-numerical values and return the sum of the numerical elements
+  it("given an array containing non-numerical values, returns the sum of the numerical values", () => {
+    expect(sum(["I", 2, "am", -1000, "Lord", "200", "Voldemort", 10])).toEqual(
+      -988
+    );
+  });
+  // Given an array with only non-number values
+  // When passed to the sum function
+  // Then it should return the least surprising value given how it behaves for all other inputs
+  it("given an array with only non-numerical values, returns 0", () => {
+    expect(sum(["I", "am", "Lord", "Voldemort"])).toEqual(0);
+  });
+
+  // Additional test: only positive integers
+  it("given an array with only positive integers, returns the sum of the elements", () => {
+    expect(sum([1, 2, 3, 100])).toEqual(106);
+  });
+});

Sprint-1/refactor/includes.js

@@ -1,8 +1,7 @@
 // Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
+  for (const element of list) {
     if (element === target) {
       return true;
     }

Sprint-1/stretch/aoc-2018-day1/solution.js

@@ -0,0 +1,17 @@
+const fs = require("fs");
+
+let frequencies;
+
+// read the input file and convert the input elements into numbers
+try {
+  const data = fs.readFileSync("./input.txt", "utf8");
+  const inputData = data.split("\n").filter((line) => line.trim() !== "");
+  frequencies = inputData.map(Number);
+} catch (err) {
+  console.error("Error reading file:", err);
+}
+
+function getFrequenciesSum(frequencies) {
+  return frequencies.reduce((acc, curr) => acc + curr, 0);
+}
+console.log(getFrequenciesSum(frequencies)); // result is 529