London | 26-ITP-May | Russom Gebremeskel | Sprint 1 | Coursework

Sprint-1/fix/median.js

@@ -6,9 +6,21 @@
 // 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;
-}
+  if (!Array.isArray(list) || list.length === 0) {
+    return null;
+  }
+
+  const numbers = list.filter((item) => typeof item === "number");
+  if (numbers.length === 0) {
+    return null;
+  }
 
+  numbers.sort((a, b) => a - b);
+  const middleIndex = Math.floor(numbers.length / 2);
+
+  if (numbers.length % 2 === 0) {
+    return (numbers[middleIndex - 1] + numbers[middleIndex]) / 2;
+  }
+  return numbers[middleIndex];
+}
 module.exports = calculateMedian;

Sprint-1/fix/median.test.js

@@ -13,7 +13,8 @@ describe("calculateMedian", () => {
     { input: [1, 2, 3, 4], expected: 2.5 },
     { input: [1, 2, 3, 4, 5, 6], expected: 3.5 },
   ].forEach(({ input, expected }) =>
-    it(`returns the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
+    it(`returns the median for [${input}]`, () =>
+      expect(calculateMedian(input)).toEqual(expected))
   );
 
   [
@@ -24,17 +25,26 @@ describe("calculateMedian", () => {
     { input: [110, 20, 0], expected: 20 },
     { input: [6, -2, 2, 12, 14], expected: 6 },
   ].forEach(({ input, expected }) =>
-    it(`returns the correct median for unsorted array [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
+    it(`returns the correct median for unsorted array [${input}]`, () =>
+      expect(calculateMedian(input)).toEqual(expected))
   );
-
-  it("doesn't modify the input array [3, 1, 2]", () => {
+ it("doesn't modify the input array [3, 1, 2]", () => {
     const list = [3, 1, 2];
     calculateMedian(list);
     expect(list).toEqual([3, 1, 2]);
   });
-
-  [ 'not an array', 123, null, undefined, {}, [], ["apple", null, undefined] ].forEach(val =>
-    it(`returns null for non-numeric array (${val})`, () => expect(calculateMedian(val)).toBe(null))
+
+  [
+    "not an array",
+    123,
+    null,
+    undefined,
+    {},
+    [],
+    ["apple", null, undefined],
+  ].forEach((val) =>
+    it(`returns null for non-numeric array (${val})`, () =>
+      expect(calculateMedian(val)).toBe(null))
   );
 
   [
@@ -45,6 +55,6 @@ describe("calculateMedian", () => {
     { input: [3, "apple", 1, null, 2, undefined, 4], expected: 2.5 },
     { input: ["banana", 5, 3, "apple", 1, 4, 2], expected: 3 },
   ].forEach(({ input, expected }) =>
-    it(`filters out non-numeric values and calculates the median for [${input}]`, () => expect(calculateMedian(input)).toEqual(expected))
-  );
-});
+    it(`filters out non-numeric values and calculates the median for [${input}]`, () =>
+      expect(calculateMedian(input)).toEqual(expected))
+  )});

Sprint-1/implement/dedupe.js

@@ -1 +1,14 @@
-function dedupe() {}
+function dedupe(arr) {
+  const elements = [];
+  for (const item of arr) {
+    if (!elements.includes(item)) {
+      elements.push(item);
+    }
+  }
+  if (elements.length === arr.length) {
+    return arr.slice();
+  }
+  return elements;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,28 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 // 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");
+//test.todo("given an empty array, it returns an empty array");
+test("given an empty array, it returns an empty array", function() {
+    console.log(dedupe)
+    expect(dedupe([])).toEqual([]);
+
+});
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
+test("given non duplicate array, it returns a copy of the array", function () {
+  const array = [1, 2, 3];
+  const result = dedupe(array);
+  expect(result).toEqual(array);
+});
 
 // Given an array of strings or numbers
-// When passed to the dedupe function
+// 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.
+test("given an array of strings or numbers, it returns the original occurrence of the array", function () {
+  const array = [1, "c", 2, 3, "d"];
+  const result = dedupe(array);
+  expect(result).toEqual(array);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,12 @@
 function findMax(elements) {
+  let largestNum;
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number") {
+      if (largestNum === undefined || elements[i] > largestNum) {
+        largestNum = elements[i];
+      }
+    }
+  }
+  return largestNum;
 }
-
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,48 @@ const findMax = require("./max.js");
 // 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");
+test("given an empty array, returns -Infinity", function() {
+    expect(findMax([])).toBeUndefined();
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
+test("given an array, with one number returns that number", function () {
+    expect(findMax([5])).toBe(5);
+});
 
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
+test("given an array with positive and negative numbers, returns the largest", function () {
+  expect(findMax([-1, -5, 1, 4])).toBe(4);
+});
 
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
+test("given an array with negative numbers, returns the closest to zero", function () {
+  expect(findMax([-3, -2, -1])).toBe(-1);
+});
 
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("given an empty array, returns -Infinity", function () {
+  expect(findMax([6.5, 1.7, 2.3])).toBe(6.5);
+});
 
 // Given an array with non-number values
 // When passed to the max function
 // Then it should return the max and ignore non-numeric values
+test("given an array with non numeric value, returns the max ignoring the non numeric value", function () {
+  expect(findMax([-1, -5, 1, 4])).toBe(4);
+});
 
 // 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
+test("given an array with only non number values, returns the least surprising value", function () {
+  expect(findMax(["a", "b", "c"])).toBe(undefined);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,20 @@
 function sum(elements) {
+  let sum = 0;
+  let hasNumber = false;
+
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number") {
+      sum += elements[i];
+      hasNumber = true;
+    }
+  }
+  if (hasNumber === false && elements.length >0) {
+    return undefined;
+  }
+  return sum;
 }
 
+let numbers = ["c", "b", "hi", 1];
+console.log(sum(numbers));
+
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,42 @@ const sum = require("./sum.js");
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+test("given an empty array, returns 0", function() {
+    expect(sum([])).toBe(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+test("given an array with just one number, returns that number", function() {
+   expect(sum([1])).toBe(1);
+});
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+test("given a negative array, returns the sum", function() {
+    expect(sum([-4, -2, -1])).toBe(-7);
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
+test("given a decimal array, returns the sum", function() {
+  expect(sum([1.9, 3.1, 2.7])).toBe(7.7);
+});
 
 // 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
+test("given a mixed array, returns only the sum of numbers ", function() {
+    expect(sum(["c", 3, 4, "hi", 7])).toBe(14);
+});
 
 // 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
+
+test("given an array of non-numeric value, returns undefined", function() {
+    expect(sum(["b", "hello", "y"])).toBe(undefined);
+});

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/refactor/includes.test.js

@@ -36,3 +36,4 @@ test("searches for null", () => {
 
   expect(currentOutput).toEqual(targetOutput);
 });
+// test checked and passed.