The Journey of #100DaysOfCode (@henna_dev)

henna.s · 2022-04-29T16:19:47.319Z

#Day82 of #100DaysOfCode

Today, I went to the office in need of human connections I don’t survive working in silos as my situation is currently and office visit absolutely did me good… I may make frequent visits

Today I went back to my unfinished Intermediate JavaScript section and wrote a blog on implementing modules in Browser

Medium – 30 Apr 22

Implementation of Modules in JavaScript: ES6

Today I was in the office, since I mostly work independently, and remote, I was in need of human connections, so office for the win ;)

Reading time: 3 min read

I am absolutely pleased finishing 82nd Day today, 18 more to go… but there are still soo many things I want to learn…

Until tomorrow

henna.s · 2022-04-30T21:28:38.606Z

#Day83 of #100DaysOfCode

Today was a good day I was going through a bad week and today I said to myself " Enough, Get Over It " Lol… I partly give credits to my husband I realized I am a sensitive person, I get too attached to stuff, which leads to disappointments and drains my energy…

I visited Pet Store today in need of some dopamine and I got my dose We decided to buy 2 dwarf bunnies, they are still young and will call us in a week… Can’t wait to have them home

Husband seeing the Fishes: They are having a scrum meeting…

Pet House1280×1280 312 KB

I continued on the modules in the ES6 section:

Renaming Imports to avoid Naming Collisions

what happens if two modules that are imported have the same function name like greet below

/* inside greeterEspanol.js */
const greet = () => {
  console.log('hola');
}
export { greet };
 
/* inside greeterFrancais.js */
const greet = () => {
  console.log('bonjour');
}
export { greet };

The following syntax will give an error that the identifier greet has already been defined.

import { greet } from 'greeterEspanol.js';
import { greet } from 'greeterFrancais.js';

There is a syntax for renaming imported resources by adding in the keyword as like:

import { exportedResource as newlyNamedResource } from '/path/to/module'

so two same greet functions can be renamed like below:

/* main.js */
import { greet as greetEspanol } from 'greeterEspanol.js';
import { greet as greetFrancais } from 'greeterFrancais.js';
 
greetEspanol(); // Prints: hola
greetFrancais(); // Prints: bonjour

Default Exports and Imports

Every module also has the option to export a single value to represent the entire module called the default export . Often, though not always, the default export value is an object containing the entire set of functions and/or data values of a module.

The syntax for exporting a default object looks like this:

const resources = { 
  valueA, 
  valueB 
}
export { resources as default };

With this syntax, the object containing the module’s resources is first declared and then exported.
It appears resources object is being exported as a named export, but the clause as default renames the exported object to default , a reserved identifier that can only be given to a single exported value.

The shorthand syntax for the same is:

const resources = {
  valueA,
  valueB
}
export default resources;

Importing default values

The syntax for importing default exports looks like this:

import importedResources from 'module.js';

It should be noted that if the default export is an object, the values inside cannot be extracted until after the object is imported, like so:

// This will work...
import resources from 'module.js'const { valueA, valueB } = resources; 

// This will not work...
import { valueA, valueB } from 'module.js'

Tomorrow will continue with a challenge …

Have a good Weekend…

henna.s · 2022-05-01T22:05:27.080Z

#Day84 of #100DaysOfCode

It was a rainy day, but the day went by fine. I was observant of nature around… I watched a kid emptying his packet of crisps to feed the birds, I also felt sad for Sunday market sellers who had few customers because of rain. We had a coffee and churros

My husband went for Gaurav Kapoor standing comedy show while I spent my evening by myself, I had a good lunch at Nandos and spent time on my presentation. I finished a practice challenge on modules, during which I realized, I need to do some codewars to keep my Javascript in check.

Both of the projects are on Github. Tomorrow I will continue work on my presentation.

WorkAround Explorer Challenge to practice modules

github.com

hennasingh/WorkAround-Explorer/blob/master/README.md

# WorkAround-Explorer

Pseudo Project to understand module implementation in Javascript Browser. The salaryData.js contains sample salary data. The data is filtered via few functions to get subsets of data by role and by company.

The project includes a web app that allow users to choose specific roles and companies in the tech industry to see the following information:

The salary for the chosen role at the chosen company.
The industry average for the chosen role.
The average salary at the chosen company across all roles.
The industry average salary across all roles and all companies.

WorkAround now wants to release a new web application called WorkAround Explorer to make their data more easily viewable. This web app should allow users to choose specific roles and companies in the tech industry to see the salary information. The below is a static image of one such combination. 

<img width="858" alt="image" src="https://user-images.githubusercontent.com/22836317/166163714-6c8965e0-0f84-4fa5-be9e-43fd7394e9c3.png">

The objective of the project was to connect files using **import** and **export** modules.


### Please Note: This requires a local server running on the machine

First Problem on Codewars

github.com

hennasingh/Codewars/blob/master/DNA-RNA-Conversion/readMe.md

Deoxyribonucleic acid, DNA is the primary information storage molecule in biological systems. It is composed of four nucleic acid bases Guanine ('G'), Cytosine ('C'), Adenine ('A'), and Thymine ('T').

Ribonucleic acid, RNA, is the primary messenger molecule in cells. RNA differs slightly from DNA its chemical structure and contains no Thymine. In RNA Thymine is replaced by another nucleic acid Uracil ('U').

Create a function which translates a given DNA string into RNA.

For example:

`"GCAT"  =>  "GCAU"`

The input string can be of arbitrary length - in particular, it may be empty. All input is guaranteed to be valid, i.e. each input string will only ever consist of 'G', 'C', 'A' and/or 'T'.

Until tomorrow

henna.s · 2022-05-02T21:57:13.703Z

#Day85 of #100DaysOfCode

Today was a good day, I spent some time walking along the coast and worked on my Devoxx presentation. I am happy with the current workflow.

Today I spent time on some more codewars and read about mocha and chai test cases and documented that A day spent well

Medium – 2 May 22

Testing in JavaScript: Mocha and Chai

Today was a holiday from work and ended up a productive day. We enjoyed a good English breakfast, walked along the coast, and paid a visit…

Reading time: 4 min read

Codewars Problems on Github (String repeat and Average)

GitHub

GitHub - hennasingh/Codewars

Contribute to hennasingh/Codewars development by creating an account on GitHub.

Until tomorrow…

henna.s · 2022-05-03T22:26:07.203Z

#Day86 of #100DaysOfCode

The last two weeks have been difficult but I am in a much better place now. I made peace with things beyond my control. My tarot card prediction also highlighted the same

I am freaking out a bit as I am only 9 days away from my Devoxx talk and I still have a long way to go to finish and practice but I am hopeful I will be able to do it… because I don’t have any alternative

Today I spent most of the time understanding Realm backend, the task tracker tutorial uses a lot of functions, triggers, and even partition strategies… I am appreciative of @Nathan_Contino from the docs team, for being patient with me and answering my never-ending questions…

Some of the functions I understood

CreateNewUserDocument

This function is called when a new user registers on the application

exports = async function createNewUserDocument({user}) {
  const cluster = context.services.get("mongodb-atlas");
  const users = cluster.db("tracker").collection("User");
  return users.insertOne({
    _id: user.id,
    _partition: `user=${user.id}`,
    name: user.data.email,
    canReadPartitions: [`user=${user.id}`],
    canWritePartitions: [`project=${user.id}`],
    memberOf: [
      {"name": "My Project", "partition": `project=${user.id}`}
    ],
  });
};

This is a hybrid partition strategy approach, user, and channel. Learn more on partition strategies.

The most interesting part was Sync permissions. It checks for read and write partitions by calling functions:

canReadPartition

exports = async function(partitionValue) {
  const cluster = context.services.get("mongodb-atlas");
  const userCollection = cluster.db("tracker").collection("User");
  try {
    const user = await userCollection.findOne({ _id: context.user.id });
    // If the user's canReadPartitions array contains the partition, they may read the partition
    return user.canReadPartitions && user.canReadPartitions.includes(partitionValue);
  } catch (error) {
    console.error(`Couldn't find user ${context.user.id}: ${error}`);
    return false
  }
}

canWritePartition

exports = async function(partitionValue) {
  const cluster = context.services.get("mongodb-atlas");
  const userCollection = cluster.db("tracker").collection("User");
  try {
    const user = await userCollection.findOne({ _id: context.user.id });
    // If the user's canWritePartitions array contains the partition, they may write to it
    return user.canWritePartitions && user.canWritePartitions.includes(partitionValue);
  } catch (error) {
    console.error(`Couldn't find user ${context.user.id}: ${error}`);
    return false
  }
};

I started a new topic in JavaScript: Asynchronous Operations

An asynchronous operation is one that allows the computer to “move on” to other tasks while waiting for the asynchronous operation to complete. Asynchronous programming means that time-consuming operations don’t have to bring everything else in our programs to a halt.

Operations like making a network request or querying a database can be time-consuming, but JavaScript allows us to execute other tasks while awaiting their completion.

What is a Promise?

Promises are objects that represent the eventual outcome of an asynchronous operation. A Promise object can be in one of three states:

Pending : The initial state— the operation has not completed yet.
Fulfilled : The operation has completed successfully and the promise now has a resolved value . For example, a request’s promise might resolve with a JSON object as its value.
Rejected : The operation has failed and the promise has a reason for the failure. This reason is usually an Error of some kind.

All promises eventually settle, enabling to write the logic for what to do if the promise fulfills or if it rejects.

That is all for today. Tomorrow will spend time on the presentation and Restaurant App.

Cheers,

henna.s · 2022-05-04T21:28:11.264Z

#Day87 of #100DaysOfCode

Adulthood is hard, adjusting to new situations is hard, and bonding with someone is sometimes hard… Lol… The only things I can think of now are the hard things… I wish life was easier but then some would say, where’s the fun in that…

Today was okayish, my morning went well… I had a one-day 5:00 am club wake-up… I was able to add more details to my presentation and I also answered a few realm queries on our forums.

I tried to understand the difference between User Objects, Custom-user-data and User meta-data. I have to say it messed up my brain.

I found out custom-user data is only a convenience thing, it pre-fetches the custom user-data object so it’s accessible from the user object in the functions, w/o having to query a realm or MongoDB Atlas. Custom user data is only refreshed when the user’s login token gets refreshed, so it can be up to 20 minutes old at any time. So, it’s better to just query MongoDB directly in the functions

I made some progress on Restaurant App, instead of using a click-listener on the marker, I will have a menu option to click and start Friends Activity. Here I will have a function to add the friend and then share the location with him.

The next part left is how will the friend receive this data and how will this be displayed on Map. It has been a good experience working on this application, but I wish I had more time to streamline my thoughts…

I am a bit exhausted today so that’s all for today.

Until tomorrow,

henna.s · 2022-05-05T22:22:19.686Z

#Day88 of #100DaysOfCode

Today was a difficult day, most of my days are like that now… One day I am fine and the next I am not. Every day feels like a fight I am glad to have a supportive partner…

I visited the Pet store again for my dopamine, I can’t wait to have my bunnies home… I named them as well “Onyx and Buster”, black and orange white…

Today I continued on Restaurant App, I shared the concept with John who is a genius engineer, and got some suggestions that I implemented. It will take some time to finish it completely. I feel so dumb Even the easiest of tasks appear hard to me now…

I read and documented a post on spinning up a local server. I dint test it with javascript code which I would do perhaps another day.

Medium – 5 May 22

How I spin up a local Server

What does it mean to “spin up a server” and how can you do it?

Reading time: 3 min read

Until tomorrow

henna.s · 2022-05-06T22:54:03.004Z

#Day89 of #100DaysOfCode

Today was a productive day, I felt relieved after speaking my heart out to the person who actually put me in that state… Well that’s how life works The person who makes you smile is also the person who makes you cry

I made good progress in Restaurant App. I completely revised the structure as John suggested. He is a genius, so what he says is always true without a doubt I am glad I reached out in time.

Since my previous state of the app was not taking into account offline access, I restructured it to make offline access possible. I downloaded all data from Atlas and then provided dropdown boxes to select locations or cuisine from.

The next part is displaying the list of restaurants in that location or as per cuisine and then allowing the user to give rating.

My Activity code is as below:

   private fun searchCuisines() {
        val config = SyncConfiguration.Builder(user!!, "NewYork")
            .waitForInitialRemoteData()
            .build()

        Timber.d("Opening Realm instance Asynchronously")
        /**
         * Should print false if its opening for the first time
         */
        Timber.d("${File(config.path).exists()}")

        Realm.getInstanceAsync(config, object: Realm.Callback() {
            override fun onSuccess(realm: Realm) {

                val allData: RealmResults<Restaurant> = realm.where<Restaurant>().distinct("cuisine").findAll()
                displayCuisineDropdown(allData)
            }
        })
    }

    private fun displayCuisineDropdown(allData: RealmResults<Restaurant>) {
        Timber.d("Synced Cuisine count ${allData.size}")
        binding.progress.visibility = View.GONE
        val list = ArrayList<String?>()

        allData.forEach{
            list.add(it.cuisine)
        }
        val arrayAdapter = ArrayAdapter(this, R.layout.dropdown_cuisine, list)
        binding.autoCompleteCuisine.setAdapter(arrayAdapter)

        binding.autoCompleteCuisine.addTextChangedListener(object: TextWatcher{
            override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {

            }

            override fun onTextChanged(value: CharSequence?, p1: Int, p2: Int, p3: Int) {
                val intent = Intent(applicationContext, RestaurantListActivity::class.java)
                intent.putExtra("CUISINE",value.toString()!!)
                intent.putExtra("FLAG","cuisine")
                startActivity(intent)
            }

            override fun afterTextChanged(p0: Editable?) {

            }
        })
    }

    private fun searchLocations() {

        val config = SyncConfiguration.Builder(user!!, "NewYork")
            .waitForInitialRemoteData()
            .build()

        Timber.d("Opening Realm instance Asynchronously")
        /**
         * Should print false if its opening for the first time
         */
        Timber.d("${File(config.path).exists()}")

        Realm.getInstanceAsync(config, object: Realm.Callback() {
            override fun onSuccess(realm: Realm) {

                val allData: RealmResults<Restaurant> = realm.where<Restaurant>().distinct("borough").findAll()
                displayLocationDropdown(allData)

            }
        })
    }

    private fun displayLocationDropdown(allData: RealmResults<Restaurant>) {
        Timber.d("Synced Location count ${allData.size}")
        binding.progress.visibility = View.GONE
        val list = ArrayList<String?>()

        allData.forEach{
            list.add(it.borough)
        }
        val arrayAdapter = ArrayAdapter(this, R.layout.dropdown_location, list)
        binding.autoCompleteLocation.setAdapter(arrayAdapter)

        binding.autoCompleteLocation.addTextChangedListener(object: TextWatcher {
            override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {
            }

            override fun onTextChanged(value: CharSequence?, p1: Int, p2: Int, p3: Int) {
                val intent = Intent(applicationContext, RestaurantListActivity::class.java)
                intent.putExtra("LOCATION",value.toString()!!)
                intent.putExtra("FLAG","location")
                startActivity(intent)
            }

            override fun afterTextChanged(p0: Editable?) {
            }

        })
    }

The UI looks as below

NewYork Restaurant750×1370 93.5 KB

Until tomorrow…

henna.s · 2022-05-07T22:22:39.733Z

#Day90 of #100DaysOfCode

Today was a productive Saturday… We had a good breakfast, I made good progress on my Restaurant app. I was hoping I would finish it but I got stuck at the last logic… but I am hopeful I will be able to finish it tomorrow

I also visited PetStore to check my bunnies… but one of them got a stomach infection and they were all in quarantine, now we will have to wait for another week. So we are getting this black and white pair…

My Bunnies <3960×1280 347 KB

I made Restaurant List Activity and Restaurant Detail, I am left with implementing the logic of rating.

  val extras = intent.getStringExtra("FLAG")

        Timber.d("Getting Realm config ")
        val config = SyncConfiguration.Builder(newYorkApp.currentUser()!!, "NewYork")
            .build()

        if(extras.equals("location")){
            val location = intent.getStringExtra("LOCATION")
            title =  location!!
            displayRestaurantAt(location, config)
            
        }else {
            val cuisine = intent.getStringExtra("CUISINE")
           title = cuisine!!
            displayRestaurantWith(cuisine, config)
        }

        Timber.d("partition is $extras")
        recyclerView = binding.rvList
        recyclerView.layoutManager = LinearLayoutManager(this)
    }

    private fun displayRestaurantWith(cuisine: String, config: SyncConfiguration) {

        Realm.getInstanceAsync(config, object: Realm.Callback() {
            override fun onSuccess(realm: Realm) {

                val restaurantList: RealmResults<Restaurant> = realm.where<Restaurant>()
                    .equalTo("cuisine", cuisine).findAll()
                updateUI(restaurantList)
            }
        })
    }

    private fun displayRestaurantAt(location: String, config: SyncConfiguration) {

        Realm.getInstanceAsync(config, object: Realm.Callback() {
            override fun onSuccess(realm: Realm) {

                val restaurantList: RealmResults<Restaurant> = realm.where<Restaurant>()
                    .equalTo("borough", location).findAll()
                updateUI(restaurantList)
            }
        })
    }

    private fun updateUI(restaurantList: RealmResults<Restaurant>) {

        Timber.d("Synced restaurants count ${restaurantList.size}")
        binding.progress.visibility = View.GONE

        //Timber.d(restaurantList.asJSON())

        adapter = RestaurantAdapter(restaurantList)
        recyclerView.adapter = adapter
        recyclerView.addItemDecoration(DividerItemDecoration(this, DividerItemDecoration.VERTICAL))
    }

The UI looks like the below, the detail screen is still WIP

List Of Restaurants688×1280 66.9 KB

Detail Screen688×1280 74.7 KB

Until Tomorrow…

henna.s · 2022-05-08T20:22:04.402Z

#Day91 of #100DaysOfCode

Today was an amazing day. I wrapped up my Restaurant App and am pretty much happy with what I have implemented and my nervousness is piling up for my talk next week…

We visited Sunday Market, had a coffee with cheese onion, and cinnamon twisters, and visited Petstore to see our bunnies fills my heart with so much love looking at them I really need to pay more attention to other better things and get less attached to work…

So I modified Restaurant Detail Activity, I also did error handling today and got to know soo much about Realm… I am last bit stuck on updating my embedded document. I will either have to create a new collection or will have to wait for the engineer to give me a resolution because I don’t know… :-/

So my Detail Activity looks as below:


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        binding = ActivityRestaurantDetailBinding.inflate(layoutInflater)
        setContentView(binding.root)

         restID = intent.getStringExtra("RESTID")

         Timber.d("Setting Realm instance again")
        config = SyncConfiguration.Builder(newYorkApp.currentUser()!!, "NewYork")
            .build()

        binding.addReviewBtn.setOnClickListener{
            val input = EditText(this)
            val dialogBuilder = AlertDialog.Builder(this)
            dialogBuilder.setMessage("Add a review for this restaurant:")
                .setCancelable(true)
                .setPositiveButton("Add"){dialog, _->
                    val review = input.text.toString()
                    dialog.dismiss()
                    addReviewToDatabase(review)
                }
                .setNegativeButton("Cancel"){dialog, _ ->
                    dialog.cancel()
                }
            val dialog = dialogBuilder.create()
            dialog.setView(input)
            dialog.setTitle("Add Restaurant Review")
            dialog.show()
        }
        recyclerView = binding.rvReviews
    }

    private fun addReviewToDatabase(userReview: String) {

        val review = Reviews(review = userReview, userid = newYorkApp.currentUser()!!.id, username = newYorkApp.currentUser()!!.profile.name)

    }

    override fun onStart() {
        super.onStart()
        getRestDetail(config)
    }

    private fun getRestDetail(config: SyncConfiguration) {

        Realm.getInstanceAsync(config, object: Realm.Callback() {
            override fun onSuccess(realm: Realm) {

              val restaurant = realm.where<Restaurant>()
                    .equalTo("restaurant_id", restID).findFirst()
                reviewRealm = realm
                title = restaurant?.name
                binding.tvName.text = restaurant?.name
                 stringBuilder.append(restaurant?.address?.building).append(" ").append(restaurant?.address?.street).append(" ").append(restaurant?.address?.zipcode)
                binding.tvAddress.text = stringBuilder
                if(restaurant?.reviews?.size==0){
                    binding.tvNoReview.visibility = View.VISIBLE
                    binding.progress.visibility = View.GONE
                }else {
                    displayReviewAdapter(restaurant)
                }
            }
        })

    }

    private fun displayReviewAdapter(restaurant: Restaurant?) {
        adapter = ReviewsAdapter(restaurant!!.reviews)
        binding.tvNoReview.visibility = View.GONE
        setUpRecyclerView()
    }

    private fun setUpRecyclerView() {
        binding.progress.visibility = View.GONE

        recyclerView.layoutManager = LinearLayoutManager(this@RestaurantDetailActivity)
        recyclerView.adapter = adapter
        recyclerView.setHasFixedSize(true)
        recyclerView.addItemDecoration(DividerItemDecoration(this@RestaurantDetailActivity, DividerItemDecoration.VERTICAL))
    }

    override fun onDestroy() {
        super.onDestroy()
        recyclerView.adapter = null
        // if a user hasn't logged out when the activity exits, still need to explicitly close the realm
        reviewRealm.close()
    }

The UI is also better than before:

Detail Screen570×1250 62.9 KB

I also spent time updating my presentation. But I will take another day to finish, perhaps will wake up early morning tomorrow.

Until next update…

henna.s · 2022-05-09T22:58:33.946Z

#Day92 of #100DaysOfCode

Today was a tiring day. I spent a lot of time fixing errors I was getting in my application. Once again, many thanks to @ChristanMelchior for all his help in resolving these errors.

I absolutely had a lot of fun creating this app and dove deeper into realm. I also worked on my presentation. I am very nervous about my presentation… This happens every time I participate in a talk :-/

Some of the errors I solved:

Caused by: java.lang.IllegalArgumentException: Configurations cannot be different
 if used to open the same file.

Caused by: java.lang.IllegalArgumentException: Embedded objects cannot be 
copied into Realm by themselves. They need to be attached to a parent object


java.lang.IllegalStateException: Only use this adapter with managed RealmCollection,

The app working is as below

Until tomorrow

henna.s · 2022-05-10T22:38:24.905Z

#93Day of #100DaysOfCode

The morning started stressful as I didn’t feel too prepared for my presentation, but all fell into place by the afternoon. I had 4 practice sessions, got good feedback from 3 amazing people, and solo practice.

As it was almost 50 min talk, I got too exhausted after all the practice and I went out for a big feast to fill my stomach

Today I am doing some funny codewars.

Problem Description

Timmy & Sarah think they are in love, but around where they live, they will only know once they pick a flower each. If one of the flowers has an even number of petals and the other has an odd number of petals it means they are in love.

Write a function that will take the number of petals of each flower and return true if they are in love and false if they aren’t.

Solution

(I did the stupidest solution )

function lovefunc(flower1, flower2){
  // moment of truth
  if(flower1%2==0 && flower2%2>0 || flower2%2==0 && flower1%2>0){
    return true
  }else {
    return false
  }
}

Best Solutions

function lovefunc(flower1, flower2){
  return flower1 % 2 !== flower2 % 2;
}

function lovefunc(flower1, flower2){
  return (flower1 + flower2) % 2 === 1

Return a Negative

In this simple assignment you are given a number and have to make it negative. But maybe the number is already negative?

makeNegative(1);    // return -1
makeNegative(-5);   // return -5
makeNegative(0);    // return 0
makeNegative(0.12); // return -0.12

Solution

I can’t believe I was doing string concatenation on this… Thats the sign of exhausted brain

function makeNegative(num) {
  // Code?
  if(num<=0){
    return num
  }else {
    return num * -1
  }
}

Last Problem of the Day

Description

Given a set of numbers, return the additive inverse of each. Each positive becomes negatives, and the negatives become positives.

invert([1,2,3,4,5]) == [-1,-2,-3,-4,-5]
invert([1,-2,3,-4,5]) == [-1,2,-3,4,-5]
invert([]) == []

Solution

function invert(array) {
  
  let array1 =[]

  for(let i=0; i<array.length; i++){
    array1[i] = array[i] * -1
  }
  return array1
}

I am traveling to London tomorrow, so see you from there…

Cheers,

henna.s · 2022-05-11T23:22:40.853Z

#Day94 of #100DaysOfCode

Today was an amazing day… I came to London for my Devoxx Talk and we had Speakers Dinner tonight and I met such an amazing group of people who were soooooo friendly and I got soo much help on my Community Program Strategies… and I cant wait to start things…

I am a bit tired so will continue some codewars… Tomorrow will be a day of sessions… so will write about them.

Problem Description

Create a function with two arguments that will return an array of the first (n) multiples of (x).

Assume both the given number and the number of times to count will be positive numbers greater than 0.

Return the results as an array.

Examples:

countBy(1,10) === [1,2,3,4,5,6,7,8,9,10]
countBy(2,5) === [2,4,6,8,10]

Solution

I know this can be much better presented, but this is my first attemp

function countBy(x, n) {
  let i=0;
  let k=1;
  let z =[];
  
  for(let j=0; j<n;j++){
    z[i] = x * k;
    i++;
    k++;
  }

  return z;
}

Better Solutions

function countBy(x, n) {
    var z = [];
    for (i = 1; i <= n; i++) {
        z.push(x * i);
    }
    return z;
}

const countBy = (x, n) => Array.from({length: n}, (v, k) => (k + 1) * x)

Abbreviate a two word name

Write a function to convert a name into initials. This kata strictly takes two words with one space in between them.

The output should be two capital letters with a dot separating them.

It should look like this:

Sam Harris => S.H

patrick feeney => P.F

Solution

function abbrevName(name){

    // code away
  let space = name.indexOf(" ")
  let firstChar = name[0]
  let secondChar = name[space+1]
  return firstChar.toUpperCase() + "." + secondChar.toUpperCase()
}

That’s all today. Until tomorrow

henna.s · 2022-05-12T22:35:33.163Z

#Day95 of #100DaysOfCode

Another tiring day but full of networking and meeting amazing folks. I had the bestest day of my life… I met leaders of Dublin and London Java groups and I look forward to collaborating with them for our mobile talks…

Another session of codewars

Problem Description

Complete the square sum function so that it squares each number passed into it and then sums the results together.

For example, for [1, 2, 2] it should return 9 because 1^2 + 2^2 + 2^2 = 9

Solution

function squareSum(numbers){

  let array =  numbers.map(number => number * number)
  
  return array.reduce((one, two) => one + two, 0)
}

Sample Tests

describe("Tests", () => {
  it("test", () => {
Test.assertEquals(squareSum([1,2]), 5)
Test.assertEquals(squareSum([0, 3, 4, 5]), 50)
Test.assertEquals(squareSum([]), 0)
});
});

Problem Description

Can you find the needle in the haystack?

Write a function findNeedle() that takes an array full of junk but containing one "needle"

After your function finds the needle it should return a message (as a string) that says:

"found the needle at position " plus the index it found the needle, so:

findNeedle(['hay', 'junk', 'hay', 'hay', 'moreJunk', 'needle', 'randomJunk'])

Solution

function findNeedle(haystack) {
  // your code here
  
let index = haystack.indexOf("needle");

return "found the needle at position " + index;
}

Sample Tests

describe("Tests", () => {
  it("test", () => {
var haystack_1 = ['3', '123124234', undefined, 'needle', 'world', 'hay', 2, '3', true, false];
var haystack_2 = ['283497238987234', 'a dog', 'a cat', 'some random junk', 'a piece of hay', 'needle', 'something somebody lost a while ago'];
var haystack_3 = [1,2,3,4,5,6,7,8,8,7,5,4,3,4,5,6,67,5,5,3,3,4,2,34,234,23,4,234,324,324,'needle',1,2,3,4,5,5,6,5,4,32,3,45,54];

Test.assertNotEquals(findNeedle(haystack_1), undefined, "Your function didn't return anything");
Test.assertEquals(findNeedle(haystack_1), 'found the needle at position 3')
Test.assertEquals(findNeedle(haystack_2), 'found the needle at position 5') 
Test.assertEquals(findNeedle(haystack_3), 'found the needle at position 30')
  });
});

Problem Description

Very simple, given an integer or a floating-point number, find its opposite.

Examples:

1: -1
14: -14
-34: 34

Solution

function opposite(number) {
  //your code here
  return number * -1
}

Sample Tests

describe("Tests", () => {
  it("test", () => {
Test.assertEquals(opposite(1), -1,)
  });
});

That is all for today…

henna.s · 2022-05-13T23:04:53.361Z

#Day96 of #100DaysOfCode

Today was the D day of the talk… It was a great first experience… I wish the wifi was not that bad and then it would have gone fine… but it was cool… I got some great suggestions from people of the community and for that I am sooooo happy

For all those, who will drop by 100DaysOfCode, below is the link to the Restaurant App, I will upload the slides as well

GitHub

GitHub - hennasingh/NewYorkRestaurant: The app uses sample_restaurant...

The app uses sample_restaurant data-set from MongoDB Atlas Clutster to create mobile app using Atlas Device Sync. - GitHub - hennasingh/NewYorkRestaurant: The app uses sample_restaurant data-set fr...

Today I also studied Asynchronous Operations in JavaScript and how to construct Promise… while waiting at the airport

Medium – 13 May 22

JavaScript: Asynchronous Operations

An Asynchronous operation is one that allows the computer to “move on” to other tasks while waiting for the asynchronous operation to…

Reading time: 3 min read

That’s all today…

Cheers

henna.s · 2022-05-14T23:03:09.220Z

#Day97 of #100DaysOfCode

A sunny day spent out with friends and drinks and a good breakfast and walk.

It took me a long time to solve this codewar. I used both forEach and map method and I did not get the correct results. Took steps and then console.log everything. The problem is uploaded to Github with details.

github.com

hennasingh/Codewars/blob/master/AmountOfPoints/Problem.md

Our football team finished the championship. The result of each match look like "x:y". Results of all matches are recorded in the collection.

For example: ["3:1", "2:2", "0:1", ...]

Write a function that takes such collection and counts the points of our team in the championship. Rules for counting points for each match:

```
if x > y: 3 points
if x < y: 0 point
if x = y: 1 point
```

Notes:

there are 10 matches in the championship
0 <= x <= 4
0 <= y <= 4

I also studied setTimeout() function of Node used in Promises that takes time to resolve or reject. Will write more on this tomorrow.

Cheers,

henna.s · 2022-05-15T21:30:51.669Z

#Day98 of #100DaysOfCode

Today was cleaning and cooking day It’s been a while since I cooked… I was relaxed a bit after the Devoxx talk… I was soo nervous about it. I woke up at 3:30 am in the morning on the day and could not go back to sleep…
I look forward to finishing some more tasks this week, but let’s write on the 98th day. In continuation of Javascript Promise, which I did 2 days ago, it’s important to know how to consume and use the promises.

The Node setTimeout() Function

It is important to know how to handle Promise objects returned as a result of an asynchronous operation. setTimeout() is a Node API that uses callback functions to schedule tasks to be performed after a delay.

setTimeout() has two parameters: a callback function and a delay in milliseconds.

const delayedHello = () => {
  console.log('Hi! This is an asynchronous greeting!');
};
 
setTimeout(delayedHello, 2000);

This delay is performed asynchronously and does not stop executing the rest of the program. Asynchronous JavaScript uses something called the event-loop. After two seconds, delayedHello() is added to a line of code waiting to be run. Before it is run, the synchronous code in the program continues to run. This also means it might take more than 2 seconds.

Executing the following code by calling node app.js will give an idea

console.log("This is the first line of code in app.js.");

const usingSTO = () => {
  console.log("This is STO inside")
}

setTimeout(usingSTO, 2500)

console.log("This is the last line of code in app.js.");

Consuming Promises

The initial state of an asynchronous promise is pending but it eventually settles. Promise objects come with an aptly named .then() method. It allows to say, “I have a promise, when it settles, then here’s what I want to happen…”

.then() is a higher-order function— it takes two callback functions as arguments. These callbacks are called handlers. When the promise settles, the appropriate handler is invoked with the settled value.

The first handler, called onFulfilled , is a success handler, and contains the logic for the promise resolving.
The second handler, called onRejected , is a failure handler, and contains the logic for the promise rejecting.

If the appropriate handler is not provided, instead of throwing an error, .then() returns a promise with the same settled value as the promise it was called on. One important feature of .then() is that it always returns a promise.

Will continue on the Success and Failure Callback Functions tomorrow.

I also did one codewar today. I am trying to make this habit of solving one everyday

github.com

hennasingh/Codewars/blob/master/CategoriseMember/Problem.md

The Western Suburbs Croquet Club has two categories of membership, Senior and Open. They would like your help with an application form that will tell prospective members which category they will be placed.

To be a senior, a member must be at least 55 years old and have a handicap greater than 7. In this croquet club, handicaps range from -2 to +26; the better the player the lower the handicap.

### Input
Input will consist of a list of pairs. Each pair contains information for a single potential member. Information consists of an integer for the person's age and an integer for the person's handicap.

### Output
Output will consist of a list of string values (in Haskell and C: Open or Senior) stating whether the respective member is to be placed in the senior or open category.

#### Example
```
input =  [[18, 20], [45, 2], [61, 12], [37, 6], [21, 21], [78, 9]]
output = ["Open", "Open", "Senior", "Open", "Open", "Senior"]
```

Cheers,

henna.s · 2022-05-16T22:49:31.802Z

#Day99 of 100daysofcode

Today has been a busy day at work. After a long time, I feel relaxed, satisfied, and at peace with my work self and I look forward to doing exciting things

Let’s continue further on JavaScript Promises.

Success and Failure Callback Functions

To handle a “successful” promise, or a promise that resolved, we invoke .then() on the promise, passing in a success handler callback function:

const prom = new Promise((resolve, reject) => {
  resolve('Yay!');
});
 
const handleSuccess = (resolvedValue) => {
  console.log(resolvedValue);
};
 
prom.then(handleSuccess); // Prints: 'Yay!'

In the code, prom is a promise that will resolve to “Yay!”. handleSuccess is a function that logs the argument passed to it. The function is passed to the prom’s .then() function and is invoked when prom resolves logging Yay! to the console.

In a practical promise consumption, a promise can resolve or reject so it’s useful to provide logic in either case. Both the success and failure callback can be passed to .then()

let prom = new Promise((resolve, reject) => {
  let num = Math.random();
  if (num < .5 ){
    resolve('Yay!');
  } else {
    reject('Ohhh noooo!');
  }
});
 
const handleSuccess = (resolvedValue) => {
  console.log(resolvedValue);
};
 
const handleFailure = (rejectionReason) => {
  console.log(rejectionReason);
};
 
prom.then(handleSuccess, handleFailure);

prom is a promise that will randomly either resolve with 'Yay!' or reject with 'Ohhh noooo!' .
Two handler functions are passed to .then() . The first will be invoked with 'Yay!' if the promise resolves, and the second will be invoked with 'Ohhh noooo!' if the promise rejects.

Note: The success callback is sometimes called the “success handler function” or the onFulfilled function. The failure callback is sometimes called the “failure handler function” or the onRejected function.

Problem Description

Write a success and failure handlers for Inventory Function defined in library.js file

library.js

const inventory = {
  sunglasses: 1900,
  pants: 1088,
  bags: 1344
};

const checkInventory = (order) => {
  return new Promise((resolve, reject) => {
    setTimeout(() => {
      let inStock = order.every(item => inventory[item[0]] >= item[1]);
      if (inStock) {
        resolve(`Thank you. Your order was successful.`);
      } else {
        reject(`We're sorry. Your order could not be completed because some items are sold out.`);
      }
    }, 1000);
  })
};

module.exports = { checkInventory };

Solution in app.js

const {checkInventory} = require('./library.js');

const order = [['sunglasses', 1], ['bags', 2]];

// Solution  code below:

const handleSuccess = (resolvedValue) => {
 console.log(resolvedValue)
}

const handleFailure = (rejectedValue) => {
 console.log(rejectedValue)
}

checkInventory(order).then(handleSuccess, handleFailure)

Solved another codewar on getting the longest string from two strings.

github.com

hennasingh/Codewars/blob/master/TwoToOne/Problem.md

Take 2 strings s1 and s2 including only letters from ato z. Return a new sorted string, the longest possible, containing distinct letters - each taken only once - coming from s1 or s2.

Examples:
```
a = "xyaabbbccccdefww"
b = "xxxxyyyyabklmopq"
longest(a, b) -> "abcdefklmopqwxy"

a = "abcdefghijklmnopqrstuvwxyz"
longest(a, a) -> "abcdefghijklmnopqrstuvwxyz"
```

Tomorrow will write about using catch() with Promises.

Cheers,

henna.s · 2022-05-17T22:03:31.579Z

#Day100 of #100DaysOfCode

Today was a busy day with multiple things to finish and I also presented a talk to the team about MongoDB and Realm which was fun. and today is the final day. I finished 100-day streak, I cant believe it…
It was such an amazing experience

I studied further on JavaScript Promises

Using catch() with Promises

It’s always helpful to debug code when the code is organised into distinct sections each handling a specific task. Instead of passing both handlers into one .then() , we can chain a second .then() with a failure handler to a first .then() with a success handler and both cases will be handled.

prom
  .then((resolvedValue) => {
    console.log(resolvedValue);
  })
  .then(null, (rejectionReason) => {
    console.log(rejectionReason);
  });

To create more readable code, A different promise function: .catch() can be used.

The .catch() function takes only one argument, onRejected . In the case of a rejected promise, this failure handler will be invoked with the reason for rejection. Using .catch() accomplishes the same thing as using a .then() with only a failure handler.

prom
  .then((resolvedValue) => {
    console.log(resolvedValue);
  })
  .catch((rejectionReason) => {
    console.log(rejectionReason);
  });

If the promise rejects, .then() will return a promise with the same rejection reason as the original promise and .catch() ‘s failure handler will be invoked with that rejection reason.

The same previous code with catch() can be written as

checkInventory(order).then(handleSuccess).catch(handleFailure)

I solved an easy codewar today.

Is this a Triangle?

Given 3 sides of a triangle, return true if a triangle can be formed or otherwise false.

Solution

Applying Triangle Inequality Theorem, the sum of 2 sides must be greater than the third side

function isTriangle(a,b,c)
{
   if(a+b>c && a+c>b && b+c >a) return true
  else return false
}

Sample Tests

const { assert } = require("chai")

describe("Public tests", () => {
  it("Testing for fixed tests", () => {
    assert.strictEqual(isTriangle(1,2,2), true);
    assert.strictEqual(isTriangle(7,2,2), false);
  });
})

With this, I finish the 100 day marathon and now I am gonna go and enjoy some CTR car racing on PS4

Until we start next time…

system · 2022-08-14T05:52:08.835Z

This topic was automatically closed after 180 days. New replies are no longer allowed.