Merge branch 'CUNYTechPrep:main' into main

README.md

@@ -33,3 +33,8 @@ After each session you can:
 
 - complete [validator functions](session-01/validators.js)
 - Due: August 7, 2024 by 12pm.
+
+### Session 02
+
+- complete [exercise functions](session-02/exercise.js)
+- Due: August 14, 2024 by 12pm.

session-02/exercise.js

@@ -0,0 +1,22 @@
+/*
+  Transform the input array of strings into uppercase strings
+  For example, for the input ["cat", "hat"], return ["CAT", "HAT"]
+*/
+function transformArrayToUpper(listOfStrings) {
+  return;
+}
+
+/*
+  Write a function that returns the sum of all student ages.
+  The function will be passed an array of objects and the result
+  will be the sum of all ages.
+  - Note, not all objects will contain an age. Omit these objects.
+  For example, for the input:
+    [{ name: 'Sandra', age: 31 }, {}, { name: 'Didi', age: 20}]
+    the function should return 51
+*/
+function sumOfAllAges(listOfStudentObjects) {
+  return;
+}
+
+module.exports = { transformArrayToUpper, sumOfAllAges };

session-02/exercise.test.js

@@ -0,0 +1,47 @@
+const { transformArrayToUpper, sumOfAllAges } = require("./exercise.js");
+
+// describe(stringDescriptionOfTheGroupOfTests, functionThatHoldsTests)
+// test(stringDescription, functionThatDoesTheTest)
+
+describe("transformArrayToUpper()", () => {
+  test('should convert ["abc"] to ["ABC"]', () => {
+    expect(transformArrayToUpper(["abc"])).toEqual(["ABC"]);
+  });
+
+  test('should convert ["apple", "banana", "coconut"] to ["APPLE", "BANANA", "COCONUT",]', () => {
+    expect(transformArrayToUpper(["apple", "banana", "coconut"])).toEqual([
+      "APPLE",
+      "BANANA",
+      "COCONUT",
+    ]);
+  });
+
+  test("should convert [] to []", () => {
+    expect(transformArrayToUpper([])).toEqual([]);
+  });
+});
+
+describe("sumOfAllAges()", () => {
+  test("should return 0 for empty input", () => {
+    expect(sumOfAllAges([])).toBe(0);
+  });
+
+  test("should return 0 for inputs missing ages", () => {
+    expect(sumOfAllAges([{ gpa: 4.0 }, {}, { name: "Sally" }])).toBe(0);
+  });
+
+  test("should return 51 for inputs with ages summing to 51", () => {
+    expect(
+      sumOfAllAges([
+        { name: "Sandra", age: 31 },
+        { name: "Didi", age: 20 },
+      ])
+    ).toBe(51);
+  });
+
+  test("should return 51 and ignore inputs with missing ages", () => {
+    expect(
+      sumOfAllAges([{ name: "Sandra", age: 31 }, {}, { name: "Didi", age: 20 }])
+    ).toBe(51);
+  });
+});

session-02/functions.js

@@ -0,0 +1,34 @@
+// Named functions
+function average(a, b, c) {
+  return (a + b + c) / 3;
+}
+
+// let result = average(1, 5, 23);
+// console.log(result);
+
+console.log("calling average function: ", average(15, 20, 23));
+
+// anonymous / unnamed functions
+const add2 = function (a, b) {
+  return a + b;
+};
+
+console.log("call add2: ", add2(4, 6));
+console.log("print add2: ", add2);
+
+// Arrow functions (ES6)
+const add3 = (a, b) => {
+  // a lot of logic
+  return a + b;
+};
+
+// implicit return with single expression functions
+// (no curly braces {}, and no return statement)
+const add4 = (a, b) => a + b; // lambda-like
+
+console.log("call add4: ", add4(3, 4));
+console.log("print add4: ", add4);
+
+// single parameter arrow function
+// parentheses are optional
+// const increaseBy3 = num => num + 3;

session-02/loops.js

@@ -0,0 +1,55 @@
+// looping through arrays
+
+const fruits = ["apple", "banana", "coconut", "durian"];
+
+// While loop
+// let i = 0;
+// while (i < fruits.length) {
+//   console.log(fruits[i]);
+//   i++;
+// }
+
+// for loop
+// for (let i = 0; i < fruits.length; i++) {
+//   const fruit = fruits[i];
+//   console.log(fruit);
+// }
+
+// for-of loop (trade off, don't get the index)
+for (const fruit of fruits) {
+  console.log(fruit);
+}
+
+// 🚫 avoid for-in loops
+// for (const item in fruits) {
+//   console.log(item);
+// }
+
+// .forEach
+// function myPrint(item) {
+//   console.log("Delicious: ", item);
+// }
+// fruits.forEach(myPrint);
+
+let result = fruits.forEach((val) => {
+  console.log("Yucky:", val);
+});
+
+console.log(result);
+
+// callback function
+
+// .map() // transform/convert/change
+
+let pluralFruits = fruits.map((f) => f + "s");
+
+console.log(pluralFruits);
+console.log(fruits);
+
+// .filter
+const words = ["spray", "elite", "exuberant", "destruction", "present"];
+
+const filteredResult = words.filter((word) => word.length > 7);
+
+console.log(filteredResult);
+console.log(words);

session-02/objects-arrays.js

@@ -0,0 +1,68 @@
+const student243 = {
+  firstName: "Edwin",
+  lastName: "Cruz",
+  age: 29,
+  gpa: 4.0,
+  fullName: function () {
+    return this.firstName + " " + this.lastName;
+  },
+  bday() {
+    console.log("Happy Birthday!");
+    this.age++;
+  },
+};
+
+console.log(student243);
+student243.bday();
+console.log(student243);
+console.log(student243.fullName());
+
+// reassignment (not allowed with constant variables)
+// student243 = { firstName: "Sally", age: 42 };
+
+// referencing properties
+student243.age;
+student243["firstName"];
+
+// adding properties
+student243.major = "Science";
+student243["minor"] = "Math";
+
+console.log(student243);
+
+// removing properties
+delete student243.major;
+console.log(student243);
+
+// does the property exist
+if (student243.major) {
+  console.log("Major:", student243.major);
+} else {
+  console.log("Major not found");
+}
+
+// get all property names
+let allPropertyNames = Object.keys(student243);
+console.log(allPropertyNames);
+
+// Arrays
+const fruits = ["apple", "pear", "cherry", "plum"];
+const things = ["a", 42, null, { name: "Juan" }];
+
+// length
+console.log(fruits.length, things.length);
+
+// indexing
+console.log(fruits[1]);
+console.log(fruits[12]);
+
+// properties
+console.log(Object.keys(things)); // don't do this
+
+// adding / push
+fruits.push("Durian");
+console.log(fruits);
+
+// pop / shift
+console.log(fruits.pop(), fruits.shift());
+console.log(fruits.length);