complete feature/sprint-2

Author: mohsenzamanist

Sprint-2/debug/address.js

@@ -12,4 +12,8 @@ const address = {
   postcode: "XYZ 123",
 };
 
-console.log(`My house number is ${address[0]}`);
+console.log(`My house number is ${address["houseNumber"]}`);
+
+// Code returns undefined
+// because address is an object but it is accessed like an array
+// in an object values can be accessed by using their proper keys

Sprint-2/debug/author.js

@@ -11,6 +11,10 @@ const author = {
   alive: true,
 };
 
-for (const value of author) {
-  console.log(value);
+for (const key in author) {
+  console.log(author[key]);
 }
+
+// for iterating in an object for...in can be used
+// and each iteration it returns the key
+// then each value can be accessed

Sprint-2/debug/recipe.js

@@ -10,6 +10,10 @@ const recipe = {
   ingredients: ["olive oil", "tomatoes", "salt", "pepper"],
 };
 
-console.log(`${recipe.title} serves ${recipe.serves}
-  ingredients:
-${recipe}`);
+console.log(`${recipe.title} serves ${recipe.serves}\ningredients:`);
+recipe.ingredients.forEach((ingredient) => console.log(ingredient));
+
+// everything is logged on one line
+// console.log is logging the recipe object array as a whole
+// instead of each value of ingredients array
+// the ingredients array must be logged using a loop

Sprint-2/implement/contains.js

@@ -1,3 +1,10 @@
-function contains() {}
+function contains(obj, property) {
+  try {
+    const keys = Object.keys(obj);
+    return keys.includes(property);
+  } catch (error) {
+    throw new Error("The parameter given is not a plain JS object.");
+  }
+}
 
 module.exports = contains;

Sprint-2/implement/contains.test.js

@@ -20,16 +20,32 @@ 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({}, "key1")).toEqual(false));
 
 // Given an object with properties
 // When passed to contains with an existing property name
 // Then it should return true
+test("contains returns true when object contains the given property", () =>
+  expect(contains({ key1: "value1", key2: "value2" }, "key1")).toEqual(true));
 
 // Given an object with properties
 // When passed to contains with a non-existent property name
 // Then it should return false
+test("contains returns false when object does not contain the given property", () =>
+  expect(contains({ key1: "value1", key2: "value2" }, "key4")).toEqual(false));
 
 // Given invalid parameters like an array
 // When passed to contains
 // Then it should return false or throw an error
+it("contains returns false or throws an error if given parameter is not a valid object", () => {
+  expect(contains([], "key1")).toEqual(false);
+  expect(contains("key1:value1", "key1")).toEqual(false);
+  expect(contains(5235, "key1")).toEqual(false);
+  expect(() => contains(undefined, "key1")).toThrow(
+    "The parameter given is not a plain JS object."
+  );
+  expect(() => contains(null, "key1")).toThrow(
+    "The parameter given is not a plain JS object."
+  );
+});

Sprint-2/implement/lookup.js

@@ -1,5 +1,9 @@
-function createLookup() {
-  // implementation here
+function createLookup(countryCurrencyPairs) {
+  if (!Array.isArray(countryCurrencyPairs)) return {};
+  return countryCurrencyPairs.reduce((acc, curr) => {
+    acc[curr[0]] = curr[1];
+    return acc;
+  }, {});
 }
 
 module.exports = createLookup;

Sprint-2/implement/lookup.test.js

@@ -1,7 +1,5 @@
 const createLookup = require("./lookup.js");
 
-test.todo("creates a country currency code lookup for multiple codes");
-
 /*
 
 Create a lookup object of key value pairs from an array of code pairs
@@ -33,3 +31,24 @@ It should return:
    'CA': 'CAD'
  }
 */
+
+describe("createLookup", () => {
+  it("returns empty object if the parameter passed is not an array", () => {
+    expect(createLookup("US:USD")).toEqual({});
+    expect(createLookup(undefined)).toEqual({});
+  });
+
+  it("returns an object of country initials and currency code", () =>
+    expect(
+      createLookup([
+        ["US", "USD"],
+        ["CA", "CAD"],
+      ])
+    ).toEqual({
+      US: "USD",
+      CA: "CAD",
+    }));
+
+  it("returns an empty object if passed an empty array", () =>
+    expect(createLookup([])).toEqual({}));
+});

Sprint-2/implement/querystring.js

@@ -6,8 +6,29 @@ function parseQueryString(queryString) {
   const keyValuePairs = queryString.split("&");
 
   for (const pair of keyValuePairs) {
-    const [key, value] = pair.split("=");
-    queryParams[key] = value;
+    let key = "",
+      value = "";
+    let equalSignIndex = pair.indexOf("=");
+
+    if (equalSignIndex === -1) {
+      key = pair;
+      value = "";
+    } else {
+      key = pair.slice(0, equalSignIndex);
+      value = pair.slice(equalSignIndex + 1);
+    }
+
+    const existingKeys = Object.keys(queryParams);
+    if (key === "" && value === "") continue;
+    if (existingKeys.includes(key)) {
+      if (queryParams[key] === value) continue;
+      if (Array.isArray(queryParams[key])) {
+        queryParams[key].push(value);
+      } else {
+        const temp = queryParams[key];
+        queryParams[key] = [temp, value];
+      }
+    } else queryParams[key] = value;
   }
 
   return queryParams;

Sprint-2/implement/querystring.test.js

@@ -3,10 +3,39 @@
 // Below is one test case for an edge case the implementation doesn't handle well.
 // Fix the implementation for this test, 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("parses querystring values containing =", () => {
   expect(parseQueryString("equation=x=y+1")).toEqual({
-    "equation": "x=y+1",
+    equation: "x=y+1",
+  });
+});
+
+test("parses querystring values containing repetitive keys", () => {
+  expect(parseQueryString("a=1&b=6&a=2&a=3&b=7")).toEqual({
+    a: ["1", "2", "3"],
+    b: ["6", "7"],
+  });
+});
+
+test("parses querystring values containing repetitive keys with same values", () => {
+  expect(parseQueryString("a=1&b=6&a=2&a=3&b=6")).toEqual({
+    a: ["1", "2", "3"],
+    b: "6",
+  });
+});
+
+test("parses querystring values containing no key and value but only =", () => {
+  expect(parseQueryString("=&b=6&a=2&=&=")).toEqual({
+    a: "2",
+    b: "6",
+  });
+});
+
+test("parses querystring values missing = sign", () => {
+  expect(parseQueryString("id=5&name=mohsen&age")).toEqual({
+    id: "5",
+    name: "mohsen",
+    age: "",
   });
 });

Sprint-2/implement/tally.js

@@ -1,3 +1,9 @@
-function tally() {}
+function tally(list) {
+  if (!Array.isArray(list)) throw new Error("Not an array.");
+  return list.reduce((acc, curr) => {
+    acc[curr] = (acc[curr] || 0) + 1;
+    return acc;
+  }, {});
+}
 
 module.exports = tally;