I'm baffled by how the community response is implemented in this particular TypeScript exercise on Exercism

I am currently learning TypeScript from scratch by working on exercises available on exercism

Successfully completed the 5th exercise on Pangram.

Below is my solution:

class Pangram {

     alphabet = "abcdefghijklmnopqrstuvwxyz"

    constructor(private pangram:string) {
        this.pangram = pangram.toLowerCase().normalize()
    }

    isPangram():boolean{
        for( let letter of this.alphabet){
            if(this.pangram.indexOf(letter) < 0) 
                return false 
        }
        return true;
    }
}

export default Pangram

To enhance my skills, I am reviewing other solutions to learn more. One particular solution caught my attention because it involves regex, which I'm not yet proficient in:

class Pangram {
    constructor(private text:string) {
    }

    isPangram():boolean {
        var set = new Set(this.text.toLowerCase().replace(/[^A-Za-z]/g, ''))
        return set.size == 26        
    }
}

export default Pangram

I'm a bit confused about how the second solution works. Initially, I thought it would replace all letters with empty characters, hence having a size of zero. However, it checks for a size of 26. Without knowing how to debug, I can only run tests to confirm its accuracy, which has been successful so far.

If anyone could explain what's happening in the second solution, I'd appreciate it!

For those curious, I've included the unit tests used for this assignment:

import Pangram from './pangram'

describe('Pangram()', () => {
  // Test cases here...
})

Thank you!

Answer №1

The following code snippet...

const set = new Set(this.text.toLowerCase().replace(/[^A-Za-z]/g, ''))

This regular expression filters out all non-alphabetic characters from the input string by converting them to lowercase and storing only unique alphabetic characters in a Set. For example, new Set("pangram") will result in a set with elements "p", "a", "n", "g", "r", and "m".

A Set constructor iterates through its parameter, adding distinct elements. With the basic Latin alphabet having 26 distinct letters, a string passed to the constructor must have a size less than or equal to 26. If the size is exactly 26, then it is a pangram (contains all letters). Otherwise, it lacks at least one letter.

Hence,

str => new Set(str.toLowerCase().replace(/[^a-z]/g,'')).size === 26
efficiently checks if an input string is a pangram. Remember, balance conciseness with readability when coding!

Hope this explanation proves helpful for your coding endeavors. Happy coding!

Similar questions

If you have not found the answer to your question or you are interested in this topic, then look at other similar questions below or use the search

What is the process for generating an array of objects using JavaScript?

I am struggling to create an array of objects using JavaScript and facing errors with new lines added where I need to split the messages and collect row numbers. The row numbers should be comma-separated if it is a repetitive error message. I found a solu ...

Prevent methods from being called in a Typescript class after they have already

I encountered a scenario where I need to exclude certain methods from the return type of a class method once they have been called. Consider a class named Setup with methods step1, step2, and step3. class Setup { step1() { return this; } ...

Experiencing a problem in React JS when trying to render a component?

I encountered an error message while trying to render a component from an object. Type 'FC<Boxprops> | ExoticComponent<{ children?: ReactNode; }>' is not compatible with type 'FC<Boxprops>'. Type 'ExoticComponen ...

Top method in Angular 6 for verifying if a scrollable section has been scrolled to the very bottom

I am searching for a reliable solution in Angular 6 to determine whether a scrollable host component has reached its maximum scroll bottom. Despite my efforts, I have been unsuccessful in finding a functioning example of a function that can detect if a cu ...

"Encountered a 'Module not found: Error: Can't resolve' issue while attempting to install from GitHub. However, the standard installation process

I am currently utilizing the Quilljs JavaScript library for a project in Angular. After installing it with the following command: npm install --save quill Everything appears to be functioning correctly, and I am able to import the Quill class into my Ty ...

How can time duration be accurately represented in TypeScript?

As I work on designing an interface for my personal project, I am in need of adding a field that represents the length of time taken to complete a task. What data type and format should I use in TypeScript to express this? Below is the interface I have cr ...

Struggling to figure out webhooks with Stripe

I have encountered a strange issue while using Stripe webhooks to process payments on my website. When I set the currency to USD, it prompts me to provide an address outside of India, which is expected. However, when I change the currency to INR, the addre ...

Learn how to effortlessly move a file into a drag-and-drop area on a web page with Playwright

I am currently working with a drag-zone input element to upload files, and I am seeking a way to replicate this action using Playwright and TypeScript. I have the requirement to upload a variety of file types including txt, json, png. https://i.stack.img ...

Tips for passing the same value to two components using vuejs $emit

Can someone help with typing in Main, where the value can also be Test World? You can view a sample here >>> Sample The issue I'm facing is that when a user adds an item to the cart, the cart shows one more than it should. I've tried t ...

"How can we trigger a re-render of a React component once a promise is fulfilled? Is there a way to prevent rendering until the

Having attempted to make updates to a functional component that interfaces with an azure-devops-ui/Filter, I've encountered a situation where I am utilizing the azure-devops-extension-sdk to handle async responses. This component is intended to be use ...

What are some strategies for enhancing TypeScript/Node speed in VSCode with the help of WSL2 and Docker?

My development environment consists of VSCode running on Windows (v1.58.2) with the Remote WSL extension (v0.58.2). I have Docker Desktop (3.5.2, engine: 20.10.7) set up to work with Linux containers through the WSL2 backend. Within these containers, I a ...

Having difficulty building a react.js application using Visual Studio 2019

Currently, I am following a helpful tutorial on creating a react.js application using visual studio. At this stage, the tutorial instructs me to open the command prompt and enter the following command: webpack app.tsx --config webpack-config.js (I have ...

What is the proper way to utilize regex_replace?

Once I posted this question on Stack Overflow, I came to understand that I needed to carry out a task of replacing all matches within a string with a different string. Specifically, I wanted to replace all instances of a whitespace with `\s*' (me ...

Display the highlighted text within the input field

Is there a library available that can create an input field with a suggestions dropdown for Male and Female where typing "M" will highlight the letters "ale," allowing for autopopulation when clicked or tabbed? The same functionality should apply for typin ...

The regular expression retrieves three pieces of information from the specified range of characters: abcd efhg (abcd)

There is a string available: [18d03] Complete screen 12" (tablet) The goal is to extract the following values: $one = '18d03'; $two = 'Complete screen 12"'; $three = 'tablet'; The current attempt involves using the followi ...

Connect the names of the sheets with the data in the tables

I have a simple question: I want to connect specific sheet names in my workbook with a table that contains a range of dates. The sheet names should be something like "blablabla" + Table@1. Although I have attempted to design a solution, it doesn't se ...

When using Angular forms, the password or username may be duplicated if entered twice when pressing the

I am currently working on a basic username and password form using Angular. Here's the template I have: <label class="welcome-content">Username:</label> <input #userName type="text" id="txtLoginUsername" (keyup.enter)="loginUser(userNa ...

The specified file is not located within the 'rootDir' directory in the Cypress tsconfig.json file

I've encountered an issue while configuring Cypress in my Project, specifically with the typescript setup for Cypress. Here is the structure of my project: fronend/ - cypress/ -tsconfig.json - src/ - tsconfig.json - package.jso ...

Typing Redux Thunk with middleware in TypeScript: A comprehensive guide

I recently integrated Redux into my SPFx webpart (using TypeScript), and everything seems to be working fine. However, I'm struggling with typing the thunk functions and could use some guidance on how to properly type them. Here's an example of ...

Create a pinia state by defining it through an interface without the need to manually list out each property

Exploring the implementation of state management (pinia) within a single-page application is my current task. We are utilizing typescript, and I am inquiring about whether there exists a method to define a state based on an interface without needing to ret ...