Manchester | 26-ITP-Jan | Ofonime Edak | Sprint 1 | Data group

Sprint-1/fix/median.js

@@ -6,9 +6,18 @@
 // 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)) return null;
+  const numbers = list.filter((e) => typeof e === "number" && !isNaN(e));
+
+  if (numbers.length === 0) return null;
+  numbers.sort((a, b) => a - b);
+  const length = numbers.length;
+  const middleIndex = Math.floor(length / 2);
+  if (length % 2 === 0) {
+    return (numbers[middleIndex - 1] + numbers[middleIndex]) / 2;
+  } else {
+    return numbers[middleIndex];
+  }
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,13 @@
-function dedupe() {}
+function dedupe(arr) {
+  if (arr.length === 0) return [];
+  const dedupeArray = [];
+  for (let i = 0; i < arr.length; i++) {
+    if (!dedupeArray.includes(arr[i])) {
+      dedupeArray.push(arr[i]);
+    }
+  }
+
+  return dedupeArray;
+}
+console.log(dedupe([1, 1, 2]));
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -1,4 +1,4 @@
-const dedupe = require("./dedupe.js");
+const dedupe = require("./dedupe");
 /*
 Dedupe Array
 
@@ -16,12 +16,56 @@ E.g. dedupe([1, 2, 1]) target output: [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");
+describe("dedupe()", () => {
+  [{ input: [], expected: [] }].forEach(({ input, expected }) =>
+    it(`given an empty array, it returns an empty array [${input}]`, () => {
+      expect(dedupe(input)).toStrictEqual(expected);
+    })
+  );
+  // Given an array with no duplicates
+  // Then it should return a copy of the original array
+  [{ input: [1, 2, 3, 4], expected: [1, 2, 3, 4] }].forEach(
+    ({ input, expected }) =>
+      it(`should return same input values [${input}] without duplicate`, () => {
+        expect(dedupe(input)).toStrictEqual(expected);
+      })
+  );
 
-// Given an array with no duplicates
-// When passed to the dedupe function
-// Then it should return a copy of the original array
+  // When passed to the dedupe function
+  // Given an array with strings or numbers
+  // When passed to the dedupe function
+  // Then it should remove the duplicate values, preserving the first occurence of each element
 
-// Given an array with strings or numbers
-// When passed to the dedupe function
-// Then it should remove the duplicate values, preserving the first occurence of each element
+  [
+    { input: [1, 2, 5, 5, "a", 5, 10, 10, "a"], expected: [1, 2, 5, "a", 10] },
+    {
+      input: ["apple", "banana", "orange", "apple", "banana", 1, 3, 4, 1],
+      expected: ["apple", "banana", "orange", 1, 3, 4],
+    },
+  ].forEach(({ input, expected }) =>
+    it(`should return deduplicated array for [${input}]`, () => {
+      expect(dedupe(input)).toStrictEqual(expected);
+    })
+  );
+});
+
+test("returns a copy, not the original array", () => {
+  const input = [1, 1, 2];
+  const result = dedupe(input);
+
+  expect(result).toStrictEqual([1, 2]);
+  expect(result).not.toBe(input);
+});
+
+it("does not mutate the original array", () => {
+  const input = [2, 3, 5];
+  dedupe(input);
+
+  expect(input).toStrictEqual([2, 3, 5]);
+});
+
+test("result has only distinct elements", () => {
+  const result = dedupe([1, 1, 2, 2, 3]);
+
+  expect(new Set(result).size).toBe(result.length);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,20 @@
 function findMax(elements) {
+  if (!Array.isArray(elements)) return "invalid elements";
+  const numberList = [];
+  for (let i = 0; i < elements.length; i++) {
+    if (typeof elements[i] === "number" && !Number.isNaN(elements[i])) {
+      numberList.push(elements[i]);
+    }
+  }
+  if (numberList.length === 0) return -Infinity;
+  let max = numberList[0];
+
+  for (let i = 1; i < numberList.length; i++) {
+    if (max < numberList[i]) {
+      max = numberList[i];
+    }
+  }
+  return max;
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,76 @@ 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");
+describe("findMax()", () => {
+  [{ input: [], expected: -Infinity }].forEach(({ input, expected }) =>
+    it(`should return ${expected} for empty [${input}]`, () => {
+      expect(findMax(input)).toEqual(expected);
+    })
+  );
 
-// 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
 
-// Given an array with both positive and negative numbers
-// When passed to the max function
-// Then it should return the largest number overall
+  [{ input: [50], expected: 50 }].forEach(({ input, expected }) =>
+    it(`should return ${expected} for array [${input}]`, () => {
+      expect(findMax(input)).toEqual(expected);
+    })
+  );
 
-// 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 both positive and negative numbers
+  // When passed to the max function
+  // Then it should return the largest number overall
 
-// Given an array with decimal numbers
-// When passed to the max function
-// Then it should return the largest decimal number
+  [{ input: [2, 5, 6, -1, 0, 25, -30], expected: 25 }].forEach(
+    ({ input, expected }) => {
+      it(`should return ${expected} for positive and negative numbers in the array`, () => {
+        expect(findMax(input)).toEqual(expected);
+      });
+    }
+  );
 
-// 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 just negative numbers
+  // When passed to the max function
+  // Then it should return the closest one to zero
+  [{ input: [-1, -10, -7, -20], expected: -1 }].forEach(({ input, expected }) =>
+    it(`should return negative number nearest to zero`, () => {
+      expect(findMax(input)).toEqual(expected);
+    })
+  );
 
-// 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 decimal numbers
+  // When passed to the max function
+  // Then it should return the largest decimal number
+
+  [{ input: [0.5, 0.1, 0.56, 0.8, "1.2"], expected: 0.8 }].forEach(
+    ({ input, expected }) =>
+      it(`should return the largest decimal number from the array`, () => {
+        expect(findMax(input)).toBeCloseTo(expected);
+      })
+  );
+
+  // Given an array with non-number values
+  // When passed to the max function
+  // Then it should return the max and ignore non-numeric values
+  [
+    {
+      input: ["edak", "ofonime", "", "@", -4, 10, 6, 50, -100, "300"],
+      expected: 50,
+    },
+  ].forEach(({ input, expected }) =>
+    it(`should return max numerical value from the array`, () => {
+      expect(findMax(input)).toEqual(expected);
+    })
+  );
+
+  // 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
+  [{ input: ["peter", "", "@", "Hi"], expected: -Infinity }].forEach(
+    ({ input, expected }) =>
+      it(`should return "invalid elements" for non-numeric values`, () => {
+        expect(findMax(input)).toEqual(expected);
+      })
+  );
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,18 @@
 function sum(elements) {
+  if (!Array.isArray(elements)) return "invalid elements";
+  if (elements.length === 0) return 0;
+  const number = [];
+  for (const part of elements) {
+    if (typeof part === "number" && !Number.isNaN(x)) {
+      number.push(part);
+    }
+  }
+  if (number.length === 0) return "invalid elements";
+  let sumOfNum = 0;
+  for (let i = 0; i < number.length; i++) {
+    sumOfNum += number[i];
+  }
+  return sumOfNum;
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -10,27 +10,73 @@ 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()", () => {
+  // Given an empty array
+  // When passed to the sum function
+  // Then it should return 0
+  [{ input: [], expected: 0 }].forEach(({ input, expected }) =>
+    it(`should return ${expected} for [${input}]`, () => {
+      expect(sum(input)).toEqual(expected);
+    })
+  );
+
+  // Given an array with just one number
+  // When passed to the sum function
+  // Then it should return that number
+
+  [{ input: [30], expected: 30 }].forEach(({ input, expected }) =>
+    it(`should return ${expected} for [${input}]`, () => {
+      expect(sum(input)).toEqual(expected);
+    })
+  );
+
+  // Given an array containing negative numbers
+  // When passed to the sum function
+  // Then it should still return the correct total sum
+
+  [{ input: [-1, -3, -4, -11], expected: -19 }].forEach(({ input, expected }) =>
+    it(`should return ${expected} for [${input}]`, () => {
+      expect(sum(input)).toEqual(expected);
+    })
+  );
+
+  // Given an array with decimal/float numbers
+  // When passed to the sum function
+  // Then it should return the correct total sum
+
+  [{ input: [0.5, 0.2, 0.11, 0.89, 0.3], expected: 2 }].forEach(
+    ({ input, expected }) =>
+      it(`should return ${expected} for [${input}]`, () => {
+        expect(sum(input)).toEqual(expected);
+      })
+  );
+
+  // 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
+
+  [
+    {
+      input: ["evan", 3, "mike", 20, 6, "", "/", undefined, null, 20],
+      expected: 49,
+    },
+  ].forEach(({ input, expected }) =>
+    it(`should return ${expected} for [${input}]`, () => {
+      expect(sum(input)).toEqual(expected);
+    })
+  );
+
+  // 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
+  [
+    {
+      input: ["evan", "mike", "",undefined],
+      expected: "invalid elements",
+    },
+  ].forEach(({ input, expected }) =>
+    it(`should return ${expected} for [${input}]`, () => {
+      expect(sum(input)).toEqual(expected);
+    })
+  );
+});

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;
     }