London | 26-ITP-May | Alex Jamshidi | Sprint 1 | Exercises

Sprint-1/fix/median.js

@@ -6,9 +6,13 @@
 // 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;} 
+  let numberArray = list.filter(n => Number.isFinite(n))
+  if (numberArray.length == 0) {return null};
+  numberArray.sort((a, b) => a - b)
+
+  if (numberArray.length % 2 == 1) {return numberArray[((numberArray.length - 1) / 2)]}
+  else {return (numberArray[((numberArray.length / 2))] + numberArray[((numberArray.length / 2) - 1)]) / 2}
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,11 @@
-function dedupe() {}
+function dedupe(array) {
+    const unique = [];
+    array.forEach((item) => {
+        if (!unique.includes(item)) {
+            unique.push(item);
+        }
+    });
+    return unique
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -16,13 +16,39 @@ 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");
+describe("dedupe", () => {
+  [
+    { input: [], expected: [] },
+  ].forEach(({ input, expected }) =>
+    it(`returns empty array for [${input}]`, () => expect(dedupe(input)).toEqual(expected))
+  );
+
 
 // Given an array with no duplicates
 // When passed to the dedupe function
 // Then it should return a copy of the original array
 
+  [
+    { input: [1, 2, 3], expected: [1, 2, 3] },
+    { input: [3, 2, 1, 4, 5], expected: [3, 2, 1, 4, 5] },
+    { input: ["hello", "a", "b", "c"], expected: ["hello", "a", "b", "c"] },
+    { input: [1, 2, "hello", 4, "a", 6], expected: [1, 2, "hello", 4, "a", 6] },
+  ].forEach(({ input, expected }) =>
+    it(`returns the median for [${input}]`, () => expect(dedupe(input)).toEqual(expected))
+  );
+
 // Given an array of strings or numbers
 // When passed to the dedupe function
 // Then it should return a new array with duplicates removed while preserving the 
 // first occurrence of each element from the original array.
+
+  [
+    { input: [1, 1, 2, 2, 3, 3,], expected: [1, 2, 3] },
+    { input: ["a", "a", "b", "b", "c", "c"], expected: ["a", "b", "c"] },
+    { input: ["qwe", "qwe", 3, 3, "hello", "hello" , "hello"], expected: ["qwe", 3, "hello"] },
+    { input: ["a", "a", "a", "a"], expected: ["a"] },
+    { input: [1, 2, 2, 2, 2, 2], expected: [1, 2] },
+  ].forEach(({ input, expected }) =>
+    it(`returns the median for [${input}]`, () => expect(dedupe(input)).toEqual(expected))
+  );
+});

Sprint-1/implement/max.js

@@ -1,4 +1,7 @@
-function findMax(elements) {
+function findMax(list) {
+    const numbers = list.filter(n => Number.isFinite(n));
+    if (numbers.length == 0) { return "-Infinity"}
+    else {return Math.max(...numbers)};
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -12,32 +12,72 @@ We have set things up already so that this file can see your function from the o
 
 const findMax = require("./max.js");
 
+describe("calculateMedian", () => {
 // 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");
+
+  it("empty array returns -Infinity", () => {
+    const list = [];
+    expect(findMax(list)).toEqual("-Infinity");
+  });
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
 
+  it("array with one number returns that number", () => {
+    const list = [2];
+    expect(findMax(list)).toEqual(2);
+  });
+
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
 
+  it("array with +ve and -ve numbers, returns largest number overall", () => {
+    const list = [10, -15];
+    expect(findMax(list)).toEqual(10);
+  });
+
+
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
 
+  it("array -ve numbers, returns closest to zero", () => {
+    const list = [-1, -2, -3, -15];
+    expect(findMax(list)).toEqual(-1);
+  });
+
+
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
 
+  it("array with decimal numbers should return largest decimal number", () => {
+    const list = [1.9, 2.8999, 3.1];
+    expect(findMax(list)).toEqual(3.1);
+  });
+
+
 // 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("array with non-number values, returns the max and ignore non-numeric values", () => {
+    const list = [1, "a", 2, "b", 3, "c"];
+    expect(findMax(list)).toEqual(3);
+  });
+
+
 // 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("array with only non-number values, return the least surprising value given how it behaves for all other inputs", () => {
+    const list = ["a", "b", "c"];
+    expect(findMax(list)).toEqual("-Infinity");
+  });
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,8 @@
-function sum(elements) {
+function sum(list) {
+    const numbers = list.filter(n => Number.isFinite(n));
+    let total = 0;
+    for (n of numbers) {total += n};
+    return total;
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -10,27 +10,56 @@ const sum = require("./sum.js");
 
 // Acceptance Criteria:
 
+describe("sum", () => {
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+  it("empty array returns 0", () => {
+    const list = [];
+    expect(sum(list)).toEqual(0);
+  });
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
+  it("array with one number returns number", () => {
+    const list = [1];
+    expect(sum(list)).toEqual(1);
+  });
 
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
 
+  it("array with negative numbers returns correct sum", () => {
+    const list = [-1, -2, -3];
+    expect(sum(list)).toEqual(-6);
+  });
+
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
 
+  it("array with decimal numbers returns correct sum", () => {
+    const list = [1.1, 2.2, 3.3];
+    expect(sum(list)).toEqual(6.6);
+  });
+
 // 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("array with non-number values returns sum of numerical values only", () => {
+    const list = [1, 2, "apple", 4, "banana", 3];
+    expect(sum(list)).toEqual(10);
+  });
+
 // 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("array with non-number values only returns least surprising output", () => {
+    const list = ["a", "b", "c"];
+    expect(sum(list)).toEqual(0);
+  });
+});

Sprint-1/refactor/includes.js

@@ -1,13 +1,20 @@
 // Refactor the implementation of includes to use a for...of loop
 
 function includes(list, target) {
+for (item of list) {if (item === target) {return true;}}
+    return false;
+}
+
+module.exports = includes;
+
+
+/* Old code:
+
   for (let index = 0; index < list.length; index++) {
     const element = list[index];
     if (element === target) {
       return true;
     }
   }
   return false;
-}
-
-module.exports = includes;
+*/