London | 26-ITP-May | Russom Gebremeskel | Sprint 2 | Coursework

Sprint-2/debug/address.js

@@ -12,4 +12,4 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address.houseNumber}`);

Sprint-2/debug/author.js

@@ -11,6 +11,9 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
-  console.log(value);
+for (const value in author) {
+  console.log(author[value]);
 }
+
+// The for of loop is trying to iterate through the object like an array.
+// For in loop would work better.

Sprint-2/debug/recipe.js

@@ -10,6 +10,6 @@ const recipe = {
   ingredients: ["olive oil", "tomatoes", "salt", "pepper"],
 };
 
-console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+console.log(recipe.title, "serves", recipe.serves);
+for (let ingredient of recipe.ingredients)
+   console.log(ingredient);

Sprint-2/implement/contains.js

@@ -1,3 +1,10 @@
-function contains() {}
+function contains(object, property) {
+  for (const key in object) {
+    if (object[key] === property) {
+      return true;
+    }
+  }
+  return false;
+}
 
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -16,20 +16,44 @@ as the object doesn't contains a key of 'c'
 // Given a contains function
 // When passed an object and a property name
 // Then it should return true if the object contains the property, false otherwise
+test("contains on an object with property returns true", function () {
+  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
+});
+test("contains on an object without property returns false", function () {
+  expect(contains({ a: 1, b: 2 }, "d")).toBe(false);
+});
 
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+test("contains on empty object returns false", function () {
+  expect(contains({}, "a")).toBe(false);
+});
 
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("contain on object with properties", function () {
+  expect(contains({ c: 4, d: 5 }, "c")).toBe(true);
+});
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("contains on object with non-existent property name returns false", function () {
+  expect(contains({ c: 4, d: 5 }, "x")).toBe(false);
+});
 
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("contain on invalid parameters returns false", function () {
+  expect(contains([], "0")).toBe(false);
+});
+
+// Given an object with properties
+// When passed to contains with a non-existent property name "0"
+// Then it should return false
+test("contain on with non-existent property returns false", function () {
+  expect(contains(["a", "b", "c"], "0")).toBe(false);
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,9 @@
-function createLookup() {
-  // implementation here
+function createLookup(pairs) {
+    let obj = {};
+    for (let pair of pairs) {
+      obj[pair[0]] = pair[1]
+    }
+    return obj;
 }
 
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,6 +1,13 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
+test("creates a country currency code lookup for multiple codes", function() {
+  expect(
+    createLookup([
+      ["US", "USD"],
+      ["CA", "CAD"],
+    ])
+  ).toEqual({US: "USD", CA: "CAD",});
+});
 
 /*
 

Sprint-2/implement/querystring.js

@@ -6,7 +6,12 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
+    if (!pair) {
+     continue;
+    }
+    const everything = pair.split("=");
+    const key = decodeURIComponent(everything.shift().replace(/\+/g, " "));
+    const value = decodeURIComponent(everything.join("=").replace(/\+/g, " "));
     queryParams[key] = value;
   }
 

Sprint-2/implement/querystring.test.js

@@ -3,7 +3,7 @@
 // Below are some test cases the implementation doesn't handle well.
 // Fix the implementation for these tests, and try to think of as many other edge cases as possible - write tests and fix those too.
 
-const parseQueryString = require("./querystring.js")
+const parseQueryString = require("./querystring.js");
 
 test("should parse values containing '='", () => {
   expect(parseQueryString("equation=a=b-2")).toEqual({
@@ -40,9 +40,11 @@ test("should replace '+' by ' '", () => {
 // Stretch exercise: Handling query strings that contain identical keys
 
 // Delete this test if you are not working on this optional case
+/*
 test("should store values of a key in an array when the key has 2 or more values", () => {
   expect(parseQueryString("key=value1&key=value2&key=value3&foo=bar")).toEqual({
     key: ["value1", "value2", "value3"],
     foo: "bar",
   });
 });
+*/

Sprint-2/implement/tally.js

@@ -1,3 +1,16 @@
-function tally() {}
+function tally(arr) {
+  if (!Array.isArray(arr)) {
+    throw new Error("Invalid input");
+  }
+  const count = {};
+  for (const item of arr) {
+    if (Object.hasOwn(count, item)) {
+      count[item] = count[item] + 1;
+    } else {
+      count[item] = 1;
+    }
+  }
+  return count;
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -19,16 +19,31 @@ const tally = require("./tally.js");
 // Given a function called tally
 // When passed an array of items
 // Then it should return an object containing the count for each unique item
+test("tally on an array returns an object with item", function() {
+    expect(tally(["a"])).toEqual({a: 1})
+})
 
 // Given an empty array
 // When passed to tally
 // Then it should return an empty object
-test.todo("tally on an empty array returns an empty object");
+test("tally on an empty array returns an empty object", function() {
+    expect(tally([])).toEqual({})
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test("tally on duplicate items returns count of items", function() {
+    expect(tally(["a", "a", "a"])).toEqual({a: 3})
+})
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+test("tally on invalid input throws an error", function () {
+  expect(() => tally("string")).toThrow("Invalid input");
+})
+
+test("tally on toString returns count of items", function () {
+  expect(tally(["toStrings", "toStrings"])).toEqual({ "toStrings": 2 });
+})

Sprint-2/interpret/invert.js

@@ -10,20 +10,28 @@ function invert(obj) {
   const invertedObj = {};
 
   for (const [key, value] of Object.entries(obj)) {
-    invertedObj.key = value;
+    invertedObj[value] = key;
   }
 
   return invertedObj;
 }
 
+module.exports = invert;
+
+
 // a) What is the current return value when invert is called with { a : 1 }
+// - Ony 1 is printed 
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
+// - 1 and 2
 
 // c) What is the target return value when invert is called with {a : 1, b: 2}
+// - {1: "a", 2: b}
 
 // c) What does Object.entries return? Why is it needed in this program?
+// - object.entries() returns an array of a given object's own enumerable string keyed property key-value pair
 
 // d) Explain why the current return value is different from the target output
+// - invertedObj only referenced the swapped value to key. We should have another variable to swap and reference key to value
 
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)

Sprint-2/interpret/inverts.test.js

@@ -0,0 +1,10 @@
+const invert = require("./invert.js");
+
+test("invert on an object with key-value returns key-value swapped", function () {
+  expect(invert({ x: 10, y: 20 })).toEqual({ 10: "x", 20: "y" });
+  expect(invert({ a: 1, b: 2 })).toEqual({ 1: "a", 2: "b" });
+  expect(invert({ distance1: 105, distance2: 201 }))
+  .toEqual({ 105: "distance1", 201: "distance2" });
+  expect(invert({ fruit: "apple", veg: "carrot" }))
+  .toEqual({ "apple": "fruit", "carrot": "veg" });
+});