London | 26-ITP-May | Edina Kurdi | Sprint 2 | Coursework

Sprint-2/debug/address.js

@@ -1,5 +1,8 @@
 // Predict and explain first...
 
+// address[0] will not work here as we have an object of key-value pairs. instead of square bracket notation we need the dot notation with the key
+// I would think it returns undefined.
+
 // This code should log out the houseNumber from the address object
 // but it isn't working...
 // Fix anything that isn't working
@@ -12,4 +15,4 @@ 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

@@ -1,4 +1,10 @@
 // Predict and explain first...
+// author is an object. It cannot be accessed through its values, maybe through its key, value pairs instead of "value" -
+
+//update on explanation: objects could be accessed through 3 methods, depending on whether we want the property name or property value, or the pair. :
+//1. Object.keys() collects into an array the keys (property names) ignoring the values
+//2. Object.values() collects into an array the values ignoring the property names
+//3. Object.entries() collects an array of arrays of key-value pairs
 
 // 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 +17,14 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
-  console.log(value);
+console.log(Object.values(author));
+// for (const value of author) {
+//   console.log(value);
+// }
+
+//alternative:
+let authorValues = [];
+for (const value of Object.values(author)) {
+  authorValues.push(value);
 }
+console.log(authorValues);

Sprint-2/debug/recipe.js

@@ -1,4 +1,5 @@
 // Predict and explain first...
+//in the template literal the ${recipe}`is referring to the whole object, we want the items in the ingredients of the recipe object, listed line by line.
 
 // This program should log out the title, how many it serves and the ingredients.
 // Each ingredient should be logged on a new line
@@ -10,6 +11,9 @@ const recipe = {
   ingredients: ["olive oil", "tomatoes", "salt", "pepper"],
 };
 
-console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+// const recipeKeys = Object.keys(recipe)
+// // console.log(recipeKeys)
+
+console.log(
+  `${recipe.title} serves ${recipe.serves}${"\n"}ingredients:${"\n"}${recipe.ingredients.join("\n")}`
+);

Sprint-2/implement/contains.js

@@ -1,3 +1,20 @@
-function contains() {}
+function contains(object, propertyName) {
+  if (typeof object !== "object" || object === null || Array.isArray(object)) {
+    throw new Error("Input should be an object");
+  }
+  const keysInObject = Object.keys(object);
+  return keysInObject.includes(propertyName);
+}
 
 module.exports = contains;
+
+/*
+Implement a function called contains that checks an object contains a
+particular property
+
+E.g. contains({a: 1, b: 2}, 'a') // returns true
+as the object contains a key of 'a'
+
+E.g. contains({a: 1, b: 2}, 'c') // returns false
+as the object doesn't contains a key of 'c'
+*/

Sprint-2/implement/contains.test.js

@@ -17,10 +17,23 @@ as the object doesn't contains a key of 'c'
 // When passed an object and a property name
 // Then it should return true if the object contains the property, false otherwise
 
+describe("when checking property existence", () => {
+  test("should return true if the object contains the property", () => {
+    expect(contains({ a: "apple", b: "hill" }, "a")).toBe(true);
+  });
+  test("should return false if the object does not contain the property", () => {
+    expect(contains({ a: "apple", b: "hill" }, "c")).toBe(false);
+  });
+});
+
 // Given an empty object
 // When passed to contains
 // Then it should return false
-test.todo("contains on empty object returns false");
+describe("given an empty object", () => {
+  test("should return false when passed to contains", () => {
+    expect(contains({}, "a")).toBe(false);
+  });
+});
 
 // Given an object with properties
 // When passed to contains with an existing property name
@@ -33,3 +46,18 @@ test.todo("contains on empty object returns false");
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+describe("when given invalid inputs", () => {
+  test("should throw an error if the input is not an object", () => {
+    expect(() => contains([true, 2, "hill"], "2")).toThrow(
+      "Input should be an object"
+    );
+  });
+
+  test("should throw an error if the input is not an object", () => {
+    expect(() => contains(null, "hi")).toThrow("Input should be an object");
+  });
+
+  test("should throw an error if the input is not an object", () => {
+    expect(() => contains("apple", "a")).toThrow("Input should be an object");
+  });
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,52 @@
-function createLookup() {
-  // implementation here
+function createLookup(countryCurrencyPairs) {
+  //if countryCurrencyPairs is not an array, throw error
+  if (!Array.isArray(countryCurrencyPairs)) {
+    throw new Error("Invalid input. It should be an array");
+  }
+  //if it is an empty array, throw error
+  if (countryCurrencyPairs.length === 0) {
+    throw new Error("Input should not be an empty array");
+  }
+
+  //if not all elements are an array in the array, throw an error
+  if (!countryCurrencyPairs.every(Array.isArray)) {
+    throw new Error("Invalid input. All elements should be arrays");
+  }
+
+  return Object.fromEntries(countryCurrencyPairs);
 }
 
 module.exports = createLookup;
+
+// console.log(
+//   createLookup([
+//     ["US", "USD"],
+//     ["CA", "CAD"],
+//   ])
+// );
+
+// console.log(createLookup([]));
+
+/*
+When
+ - createLookup function is called with the country-currency array as an argument
+
+Then
+ - It should return an object where:
+ - The keys are the country codes
+ - The values are the corresponding currency codes
+
+Example
+Given: [['US', 'USD'], ['CA', 'CAD']]
+
+When
+createLookup(countryCurrencyPairs) is called
+
+Then
+It should return:
+ {
+   'US': 'USD',
+   'CA': 'CAD'
+ }
+
+*/

Sprint-2/implement/lookup.test.js

@@ -1,6 +1,46 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
+describe("when given invalid inputs", () => {
+  test("should return invalid input error, if the input is an empty array", () => {
+    expect(() => createLookup([])).toThrow(
+      "Input should not be an empty array"
+    );
+  });
+  test("should return invalid input error, if the input isn't an array of arrays", () => {
+    expect(() => createLookup(["hi", "hello"])).toThrow(
+      "Invalid input. All elements should be arrays"
+    );
+  });
+  test("should return invalid input error, if the input isn't an array of arrays", () => {
+    expect(() => createLookup("hi")).toThrow(
+      "Invalid input. It should be an array"
+    );
+  });
+  test("should return invalid input error, if the input isn't an array of arrays", () => {
+    expect(() => createLookup(2)).toThrow(
+      "Invalid input. It should be an array"
+    );
+  });
+});
+
+describe("when given valid inputs", () => {
+  test("should return an object where (Input ==> Output): keys:values ==> country code: corresponding currency", () => {
+    expect(createLookup([["US", "USD"]])).toEqual({
+      US: "USD",
+    });
+  });
+  test("should return an object where (Input ==> Output): keys:values ==> country code: corresponding currency", () => {
+    expect(
+      createLookup([
+        ["US", "USD"],
+        ["CA", "CAD"],
+      ])
+    ).toEqual({
+      US: "USD",
+      CA: "CAD",
+    });
+  });
+});
 
 /*
 
@@ -9,7 +49,7 @@ Create a lookup object of key value pairs from an array of code pairs
 Acceptance Criteria:
 
 Given
- - An array of arrays representing country code and currency code pairs
+ - An array of arrays representing when given invalid inputs code pairs
    e.g. [['US', 'USD'], ['CA', 'CAD']]
 
 When

Sprint-2/implement/querystring.js

@@ -3,12 +3,37 @@ function parseQueryString(queryString) {
   if (queryString.length === 0) {
     return queryParams;
   }
-  const keyValuePairs = queryString.split("&");
 
-  for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+  //replace initial "?" if present
+  if (queryString.startsWith("?")) {
+    queryString = queryString.replace("?", "");
   }
+  //replace encoded characters
+  queryString = decodeURIComponent(queryString);
+
+  //replace "+" with " "
+  queryString = queryString.replaceAll("+", " ");
+
+  const keyValuePairs = queryString.split("&");
+
+  //filter out empty strings from the keyValuePairs array of strings
+  const filteredKeyValuePairs = keyValuePairs.filter(
+    (keyValuePair) => keyValuePair.length > 0
+  );
+
+  //assign key value pairs created by separating on the first "=" sign
+  filteredKeyValuePairs.forEach((str) => {
+    //if no "=", then the string should be the key
+    if (!str.includes("=")) {
+      const key = str;
+      queryParams[key] = "";
+    } else {
+      const indexOfFirstEqual = str.indexOf("=");
+      const key = str.slice(0, indexOfFirstEqual);
+      const value = str.slice(indexOfFirstEqual + 1);
+      queryParams[key] = value;
+    }
+  });
 
   return queryParams;
 }

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({
@@ -37,12 +37,15 @@ test("should replace '+' by ' '", () => {
   });
 });
 
+test("should delete accidental '?' if first char by accident", () => {
+  expect(parseQueryString("?colour=teal")).toEqual({ colour: "teal" });
+});
 // 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",
-  });
-});
+// // 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 +1,18 @@
-function tally() {}
+function tally(array) {
+  if (!Array.isArray(array)) {
+    throw new Error("Input should be an array");
+  }
+
+  const tallySet = {};
+
+  for (let item of array) {
+    if (!tallySet[item]) {
+      tallySet[item] = 1;
+    } else {
+      tallySet[item] += 1;
+    }
+  }
+  return tallySet;
+}
 
 module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -19,16 +19,46 @@ 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
+describe("tally()", () => {
+  // Given an array with duplicate items
+  // When passed to tally
+  // Then it should return counts for each unique item
+  describe("when given an array with a single item", () => {
+    test("should return an object with counts for that item (1)", () => {
+      expect(tally(["a"])).toEqual({ a: 1 });
+    });
+  });
+  describe("when given an array with duplicate items", () => {
+    test("should return an object with counts that item", () => {
+      expect(tally(["a", "a", "a"])).toEqual({ a: 3 });
+    });
+  });
+  describe("when given an array with duplicate items", () => {
+    test("should return an object with counts for each unique item", () => {
+      expect(tally(["a", "a", "b", "c"])).toEqual({ a: 2, b: 1, c: 1 });
+    });
+  });
+  // Given an empty array
+  // When passed to tally
+  // Then it should return an empty object
+  describe("when given an empty array", () => {
+    test("should return an empty object", () => {
+      expect(tally([])).toEqual({});
+    });
+  });
 
-// 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");
-
-// Given an array with duplicate items
-// When passed to tally
-// Then it should return counts for each unique item
-
-// Given an invalid input like a string
-// When passed to tally
-// Then it should throw an error
+  // Given an invalid input like a string
+  // When passed to tally
+  // Then it should throw an error
+  describe("when given invalid input", () => {
+    test("should throw an error for a string input", () => {
+      expect(() => tally("apple")).toThrow("Input should be an array");
+    });
+    test("should throw an error for a boolean input", () => {
+      expect(() => tally(true)).toThrow("Input should be an array");
+    });
+    test("should throw an error for a number input", () => {
+      expect(() => tally(3)).toThrow("Input should be an array");
+    });
+  });
+});