ITP -Northwest- JAN 2025 | Jan Lo | Module-Data groups | SPRINT 2 | WEEK 7

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 +11,6 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
+for (const value of Object.values(author)) {
   console.log(value);
 }

Sprint-2/debug/recipe.js

@@ -12,4 +12,4 @@ const recipe = {
 
 console.log(`${recipe.title} serves ${recipe.serves}
   ingredients:
-${recipe}`);
+  ${recipe.ingredients.join("\n")}`);

Sprint-2/implement/contains.js

@@ -1,3 +1,24 @@
-function contains() {}
+function contains(element, key) {
+    const result = element[key];
 
+    // console.log({
+    //     key,
+    //     typeKey: typeof key,
+
+    //     result,
+    //     typeResult: typeof result
+    // })
+
+    // if undefined
+      // return false as doesnt exist
+    // else, does exist!
+      // return true
+
+    if (result === undefined) return false;
+    else return true;
+
+}
+console.log(contains({a: 1, b: 2}, 'a'))
+console.log(contains({a: 1, b: 2}, 'c'))
+console.log(contains({firstName: "Cam" }, 'firstName'))
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -4,7 +4,7 @@ const contains = require("./contains.js");
 Implement a function called contains that checks an object contains a
 particular property
 
-E.g. contains({a: 1, b: 2}, 'a') // returns true
+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
@@ -20,16 +20,26 @@ as the object doesn't contains a key of 'c'
 // 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", () => {
+    expect(contains({})).toBe (false);
+});
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("contains with an existing property name", () => {
+    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("contains with a non-existent property name", () => {
+    expect(contains({a: 1, b: 2}, 'c')).toBe (false);
+});
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+test("invalid parameters", () => {
+    expect(contains(["apple", "orange", "pear"])).toBe (false);
+});
+

Sprint-2/implement/lookup.js

@@ -1,5 +1,54 @@
-function createLookup() {
-  // implementation here
+// function createLookup(countryCurrencyPairs) {
+//   for( let i = 0; i < countryCurrencyPairs.length; i++) {
+//      const countryCurrencyPair = countryCurrencyPairs[i]
+
+//     // console.log({
+//     //   countryCurrencyPairs,
+//     //   i,
+//     //   value: countryCurrencyPairs[i],
+//     //   countryCurrencyPair,
+
+//     // })
+
+//      //console.log('i am here:', countryCurrencyPairs[[i]])
+//      console.log(countryCurrencyPair[])
+
+//   }
+
+//   return countryCurrencyPairs;
+
+//   const country = countryCurrencyPair[0]
+//   const currency = countryCurrencyPair[1]
+
+//   return{[country]:currency};
+
+
+//   // implementation here
+// }
+
+// function createSingleLookup(countryCurrencyPair) {
+//   const country = countryCurrencyPair[0]
+//   const currency = countryCurrencyPair[1]
+
+//   return{[country]:currency};
+// }
+
+// console.log(createLookup([['US', 'USD'], ['CA', 'CAD']]))
+
+// console.log(createSingleLookup(['US', 'USD'])) // return { 'US': 'USD' }
+
+function createLookup(countryCurrencyPairs) {
+  return countryCurrencyPairs.reduce((lookup, pair) => {
+    const [country, currency] = pair;
+    lookup[country] = currency; 
+    return lookup;
+  }, {});  
 }
 
 module.exports = createLookup;
+
+
+// for (let i = 0; i < onlyNumbers.length; i++) {
+//   total += onlyNumbers[i];
+//   }
+//   return total;

Sprint-2/implement/lookup.test.js

@@ -1,6 +1,10 @@
 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", () => {
+  const input = [['US', 'USD'], ['CA', 'CAD']];
+  const expectedOutput = { US: 'USD', CA: 'CAD' };
+  expect(createLookup(input)).toEqual(expectedOutput);
+});
 
 /*
 

Sprint-2/implement/querystring.js

@@ -6,7 +6,8 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
+    const [key, ...valueParts] = pair.split("="); 
+    const value = valueParts.join("="); 
     queryParams[key] = value;
   }
 

Sprint-2/implement/querystring.test.js

@@ -10,3 +10,14 @@ test("parses querystring values containing =", () => {
     "equation": "x=y+1",
   });
 });
+
+test("parses an empty query string", () => {
+  expect(parseQueryString("")).toEqual({});
+});
+
+test("parses query strings with multiple key-value pairs", () => {
+  expect(parseQueryString("key1=value1&key2=value2")).toEqual({
+    "key1": "value1",
+    "key2": "value2",
+  });
+});

Sprint-2/implement/tally.js

@@ -1,3 +1,12 @@
-function tally() {}
-
-module.exports = tally;
+function tally(items) {
+    if (!Array.isArray(items)) {
+      throw new Error("Input must be an array");
+    }
+
+    return items.reduce((counts, item) => {
+      counts[item] = (counts[item] || 0) + 1;
+      return counts;
+    }, {});
+  }
+
+  module.exports = tally;

Sprint-2/implement/tally.test.js

@@ -23,12 +23,26 @@ const tally = require("./tally.js");
 // 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", () => {
+    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 an array with duplicate items", () => {
+    expect(tally(['a', 'a', 'b', 'c', 'a', 'b'])).toEqual({
+      a: 3,
+      b: 2,
+      c: 1,
+    });
+  });
 
 // Given an invalid input like a string
 // When passed to tally
 // Then it should throw an error
+
+test("tally throws an error for invalid input (string)", () => {
+    expect(() => tally("not an array")).toThrow("Input must be an array");
+  });

Sprint-2/interpret/invert.js

@@ -10,20 +10,33 @@ 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 }
+
+//Current return value: { key: 1 }
 
 // b) What is the current return value when invert is called with { a: 1, b: 2 }
 
+//Current return value: { key: 2 }
+
 // c) What is the target return value when invert is called with {a : 1, b: 2}
 
+//Target return value: { "1": "a", "2": "b" }.
+
 // c) What does Object.entries return? Why is it needed in this program?
 
+// Object.entries returns an array of [key, value] pairs from the object.
+
 // d) Explain why the current return value is different from the target output
 
+// The current implementation incorrectly assigns the value to a property literally 
+// named "key" instead of dynamically using the value as the key.
+
 // e) Fix the implementation of invert (and write tests to prove it's fixed!)

Sprint-2/interpret/invert.test.js

@@ -0,0 +1,17 @@
+const invert = require("./invert.js");
+
+test("inverts an object with one key-value pair", () => {
+  expect(invert({ a: 1 })).toEqual({ "1": "a" });
+});
+
+test("inverts an object with multiple key-value pairs", () => {
+  expect(invert({ a: 1, b: 2 })).toEqual({ "1": "a", "2": "b" });
+});
+
+test("handles an empty object", () => {
+  expect(invert({})).toEqual({});
+});
+
+test("handles objects with numeric keys and string values", () => {
+  expect(invert({ 1: "a", 2: "b" })).toEqual({ a: "1", b: "2" });
+});