London | 26-ITP-Sept | Hugh Mills | Sprint 2 | Sprint 2 coursework

Sprint-2/debug/address.js

@@ -1,5 +1,5 @@
 // Predict and explain first...
-
+// it returns undefined as it can't find 0 because this is an object its iterating with and not an array
 // This code should log out the houseNumber from the address object
 // but it isn't working...
 // Fix anything that isn't working
@@ -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

@@ -1,5 +1,6 @@
 // Predict and explain first...
-
+// value is undefined, its not seen in the code at all.
+// Ah error said it is not iterable, i didnt spot the for...of loop there, so its not seeing the value as an option in the object.
 // This program attempts to log out all the property values in the object.
 // But it isn't working. Explain why first and then fix the problem
 
@@ -11,6 +12,6 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
+for (const value of Object.values(author)) {
   console.log(value);
 }

Sprint-2/debug/recipe.js

@@ -1,5 +1,6 @@
 // Predict and explain first...
-
+// it does not make a new line as just pressing enter wont work for that.
+// I was wrong, ingredients is showing [object Object], as it wont log out a full object like this.
 // This program should log out the title, how many it serves and the ingredients.
 // Each ingredient should be logged on a new line
 // How can you fix it?
@@ -12,4 +13,4 @@ const recipe = {
 
 console.log(`${recipe.title} serves ${recipe.serves}
   ingredients:
-${recipe}`);
+${recipe.ingredients.join("\n")}`);

Sprint-2/implement/contains.js

@@ -1,3 +1,8 @@
-function contains() {}
+function contains(object, property) {
+  if (Array.isArray(object)) {
+    throw new Error("contains requires an object");
+  }
+  return property in object;
+}
 
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -19,22 +19,36 @@ as an array isn't an object
 // 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("When passed an object and a property name, returns true", () => {
+  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
+});
 
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+test("Given an empty object, returns false", () => {
+  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("Given an object with properties, returns true", () => {
+  expect(contains({ a: 1, b: 2 }, "a")).toBe(true);
+});
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("Given an object with a non-existent property name, returns false", () => {
+  expect(contains({ a: 1, b: 2 }, "c")).toBe(false);
+});
 
 // Given a value that isn't an object - an array, a string, a number,
 // null, or no argument at all
 // When passed to contains
 // Then it should throw Error("contains requires an object")
 // (careful: typeof [] and typeof null are both "object")
+test("Given an array, throws an error 'contains requires an object'", () => {
+  expect(() => contains([])).toThrow("contains requires an object");
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,6 @@
-function createLookup() {
-  // implementation here
+function createLookup(countryCurrencyPairs) {
+  const lookup = Object.fromEntries(countryCurrencyPairs);
+  return lookup;
 }
 
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,6 +1,6 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
+// test.todo("creates a country currency code lookup for multiple codes");
 
 /*
 
@@ -33,3 +33,14 @@ It should return:
    'CA': 'CAD'
  }
 */
+test("Given an array of arrays representing country code and currency code pairs should return in object", () => {
+  expect(
+    createLookup([
+      ["US", "USD"],
+      ["CA", "CAD"],
+    ])
+  ).toEqual({
+    US: "USD",
+    CA: "CAD",
+  });
+});

Sprint-2/implement/querystring.js

@@ -6,7 +6,13 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
+    if (pair === "") {
+      continue;
+    }
+    const parts = pair.split("=");
+
+    const key = decodeURIComponent(parts[0]);
+    const value = decodeURIComponent(parts.slice(1).join("="));
     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({

Sprint-2/implement/tally.js

@@ -1,3 +1,17 @@
-function tally() {}
+function tally(array) {
+  const lookup = {};
+  if (!Array.isArray(array)) {
+    throw new Error("tally requires an array");
+  }
+
+  for (const item of array) {
+    if (lookup[item]) {
+      lookup[item] += 1;
+    } else {
+      lookup[item] = 1;
+    }
+  }
+  return lookup;
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -19,16 +19,28 @@ 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("When passed an array of items should return object containing count for each", () => {
+  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("When passed an empty array should return empty object", () => {
+  expect(tally([])).toEqual({});
+});
 
 // Given an array with duplicate items
 // When passed to tally
 // Then it should return counts for each unique item
+test("When passed an array of duplicate items should return object containing correct count", () => {
+  expect(tally(["a", "a", "a"])).toEqual({ a: 3 });
+});
 
 // Given an invalid input like a string, a number, or no argument at all
 // When passed to tally
 // Then it should throw Error("tally requires an array")
+test("WGiven an invalid input  should throw error 'tally requires an array'", () => {
+  expect(() => tally("im a string")).toThrow("tally requires an array");
+});

Sprint-2/interpret/invert.js

@@ -10,20 +10,29 @@ 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 }
+// console.log(invert({ a: 1 }));
+// It is: { key: 1 }
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
+// console.log(invert({ a: 1, b: 2 }));
+// it is: { key: 2 }
 
 // c) What is the target return value when invert is called with {a : 1, b: 2}
+// it should be : { 1: "a", 2: "b" }
 
 // c) What does Object.entries return? Why is it needed in this program?
+// it is containing each key/value pair
+// it takes an object and turns it into an array
 
 // d) Explain why the current return value is different from the target output
+// its because of "invertedObj.key = value;" each time it is running its writes
+// to the same property of "key" basically overwriting the previous one.
 
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)

Sprint-2/interpret/invert.test.js

@@ -0,0 +1,31 @@
+const invert = require("./invert.js");
+
+// inverting original input
+test("Inverting original input of 1 property", () => {
+  expect(invert({ a: 1 })).toEqual({ 1: "a" });
+});
+
+// inverting original input of 2 objects and 2 properties
+test("Inverting original input of 2 properties", () => {
+  expect(invert({ a: 1, b: 2 })).toEqual({ 1: "a", 2: "b" });
+});
+
+// inverting an empty object
+test("Inverting original input correctly", () => {
+  expect(invert({})).toEqual({});
+});
+
+// Inverting an object with an empty string as a value
+test("Inverting an object with an empty string as a value", () => {
+  expect(invert({ a: "" })).toEqual({ "": "a" });
+});
+
+// Inverting an object with an empty string as a key
+test("Inverting an object with an empty string as a key", () => {
+  expect(invert({ "": 1 })).toEqual({ 1: "" });
+});
+
+// Inverting an object with multiple properties sharing the same value
+test("Inverting an object with multiple properties sharing the same value", () => {
+  expect(invert({ a: 2, b: 2, c: 2 })).toEqual({ 2: "a", 2: "b", 2: "c" });
+});