DEV Community: Do Cuong

2/11

Do Cuong — Mon, 02 Nov 2026 03:21:26 +0000

2/11
TOP - Foundation: 95%
Project: Calculator

I finished the work sooner than I thought so I have some free time to code.

Updated number1 and number2 variable that I stuck on yesterday.

I actually think up the solution while resting yesterday, just applied it today.

Good thing it work.

My Calculator can do simple math (+,-,/,*) with 2 number now.

Will keep working to improve it like TOP assignment.

1/11

Do Cuong — Sun, 01 Nov 2026 03:48:27 +0000

1/11
TOP - Foundation: 95%
Project: Calculator

Currently stuck with the logic of the Calculator app.
The part about update number1 and number2 variable.

Will keep working on it on Tuesday ( I have something to do on Monday )

I thought it would be easy but I guess not.

Actually I once made a simple calculator webpage once, with the help of AI though.

I remember I done it in half an hour. Feel very easy.
The logic was understandable. Feel simple.

And I am still stuck now.
Made me realized how much I depended on AI.
The worst part is that I didn't even realize it back then.
I thought, oh, I understand all the code, I learned new thing.
I thought I did 50% of the work by prompting, AI did the last 50%.
Now I think I did about 5-10% of the work ( or maybe less, lol )

No wonder the learning didn't retain in my memory.

31/10

Do Cuong — Sat, 31 Oct 2026 03:23:48 +0000

31/10
TOP - Foundation: 95%
Project: Calculator

Finally start building Calculator.

In script.js:
Made basic math functions
Made operate function: operate('operator', number1, number2)

In index.html
Made basic html elements: title, screen, operator buttons, number buttons, "=" button, clear button.

Will continue working on it tomorrow.

30/10

Do Cuong — Fri, 30 Oct 2026 03:32:51 +0000

30/10
TOP - Foundation: 93%
Object Basics

Completed the last 3 tasks of object basics exercises in the foundation repo:

03 - fibonacci was pretty tough

04 - getTheTittles was easy, no diff

05 - findTheOldest was tough, but I think not as tough as fibonacci

Learn about ??= at the findTheOldest task solution, pretty neat trick.
I used sort() to sort the array and get the [0] index to get the oldest. The solution was using reduce() to get the oldest though.
Seeing reduce() use for sorting was pretty cool.

Finally finished Object basics lesson.
Only Project: Calculator now.

Almost done with Foundation, it was a long and tough journey, about 4 months.

I learned a lot in this time.

29/10

Do Cuong — Thu, 29 Oct 2026 03:23:05 +0000

29/10
TOP - Foundation: 93%
Object Basics

Working with object basics exercises in the foundation repo.

Done 2/5.

The exercise 2 - checking for palindromes was really hard.
Have to go over the array method and string method a lot.

In the end I completed it, by using replaceAll to trim out the special characters and array.every() to check if each word is satisfy the condition though.
TOP solution was using filter to filter all the alphanumerical fo the string then using reverse() which I think is better than my solution

Still confuse a lot while learning but I am starting to google with confidence now, lol.

28/10

Do Cuong — Wed, 28 Oct 2026 03:24:50 +0000

28/10
TOP - Foundation: 93%
Object Basics

Done with the two array cardio challenges of Javascript30.
07 - Array Cardio Day 2 was easier than 04 - Array Cardio Day 1 imo.

First time using array.some() and array.every() method.

array.some() check if any of the item in the array satisfy for the condition.
Return true if atleast 1 item passed. If all failed then return false.

array.every() check if all the items in the array satisfy the condition.
Return true if all items passed. return false if even 1 item failed.

Pretty neat.

Tomorrow, I will work with the last part of TOP assignment, which is foundations/object basics exercises.

27/10

Do Cuong — Tue, 27 Oct 2026 04:01:41 +0000

27/10
TOP - Foundation: 93%
Object Basics

Working with Javascript30 challenges:
04 - Array Cardio Day 1 ( currently here, stuck with the last reduce practice )
07 - Array Cardio Day 2

I almost freeze when I saw all the practice challenges on Javascript30. Thought I need to do all that.

Good thing I only need to do 2 challenge, well, maybe I will work with the other challenge later.

26/10

Do Cuong — Mon, 26 Oct 2026 03:19:02 +0000

26/10
TOP - Foundation: 93%
Object Basics

Done last 2 tasks from array methods article of javascript.info.
YAy, Finally done all the tasks from this. Hardest lesson so far.

The last task which is Create keyed object from array was really hard, I need 1 hour to think for a solution.
At the end I solved it, but not by using reduce method like the web require but by using array for loop though 😅

After I checked the solution and it suddenly feel so simple though, dunno why when I was working with it it feel so hard.

Still have 2 more parts in the TOP assignment for me to practice.

25/10

Do Cuong — Sun, 25 Oct 2026 03:32:26 +0000

25/10
TOP - Foundation: 93%
Object Basics

Read through the content of object basics lesson on TOP
Learn more about object reference, how different it is compared to primitive.

Declare a primitive variable => contain a copy of the information provided to it. // get data value
Declare an object variable => contain a reference to the object provided to it. // get location

Working with the left over practice lessons from array method:
https://javascript.info/array-methods#tasks
Done 3/5 tasks

24/10

Do Cuong — Sat, 24 Oct 2026 03:30:59 +0000

24/10
TOP - Foundation: 93%
Object Basics

Great read.

Don't know if because I read about object on https://javascript.info/object. yesterday so my understanding of object feel clearer now or MDN explain easier to understand than javascript.info ( MDN's explainations often feel harder to understand than javascript.info imo )

Understand more about object property and method.
Object property is used to refer to data items inside object.
Object method refer to function inside object. (object method is still an object property though)

Learn more about this.
This refer to the current object the method is called on.
If the object has a nested object inside of it and inside of that nested object have a method with this then this here refer to the nested object, not the outer object.

Example:
const person = {
name: { first : 'John', last: 'Smith' },
lookForThis() { console.log(this) },
obj: { lookForThis() { console.log(this) }},
};

person.lookForThis() // get person object
person.obj.lookForThis() // get obj object

23/10

Do Cuong — Fri, 23 Oct 2026 03:31:56 +0000

23/10
TOP - Foundation: 93%
Object Basics

Start learning about object data type.
Read https://javascript.info/object.

Creating new object:
let obj = new Object();
or let obj = {};

Object have property. Each property consist of 2 part: key and value.
example of an object:
let user = {
name: "John",//key: 'name'( key is string data type ),value:"John"
age: 30, //key: 'age', value:30.
}

Can use dot notation to access obj value.
user.name // 'John'
user.surname = "Smith" // add new property to user obj.
delete user.name // delete property from obj.

dot notation need valid variable identifier. Mean you can't use:
user.is Admin = true;
or user."is Admin" = true;
these won't work
can use [] instead.
user["is Admin"] = true // this worked.

To check for property in obj use "key" in obj.
Example: "name" in user // true
To iterate over an obj use for (let key in obj) loop

22/10

Do Cuong — Thu, 22 Oct 2026 04:20:24 +0000

22/10
TOP - Foundation: 91%
Project: Etch-a-Sketch

Done add opacity increasing for the sketch.
I am a bit busy today so I didn't have much time to learn this morning.

Well, at least I can finally say that I am done with Etch-a-Sketch. Both the basic and the extra credit 🤓

Tomorrow will be Object basics lesson