Documentation

README.md

@@ -10,11 +10,35 @@ Just trying to learn Typescript and improve my problem solving skills.
 
 I am also trying to incorporate testing, documentation and a better GIT control.
 
+Checkout my [Notion](https://mohitjain.notion.site/Coding-Challenges-af9b8197a438447e9b455ab9e010f9a2?pvs=4) where I share how I tackled these challenges, along with my learnings.
+
 ## Structure
 
 - `src` - Contains all the source code
 - `tests` - Contains all the test files
 
+## Challenges
+
+1. [Write your own wc tool](src/1/)
+2. [Write your own JSON parser](src/2/)
+3. [Write Your Own Compression Tool](src/3/)
+4. [Write Your Own cut Tool](src/4/)
+5. [Write You Own Load Balancer](src/5/)
+6. [Write Your Own Sort Tool](src/6/)
+7. [Write Your Own Calculator](src/7/)
+8. [Write Your Own Redis Server](src/8/)
+9. [Write your own grep](src/9/)
+10. [Write Your Own uniq Tool](src/10/)
+11. [Write Your Own Web Server](src/11/)
+12. [Write Your Own URL Shortener](https://github.com/jainmohit2001/short-url)
+13. [Write Your Own diff Tool](src/13/)
+14. [Write Your Own Shell](src/14/)
+15. [Write Your Own cat Tool](src/15/)
+16. [Write Your Own IRC Client](src/16/)
+17. [Write Your Own Memcached Server](src/17/)
+18. [Write Your Own Spotify Client](https://github.com/jainmohit2001/spotify-client)
+19. [Write Your Own Discord Bot](src/19/)
+
 ## Installation
 
 The following command will build all the .ts files present in `src` folder into a new `build` folder.

src/1/README.md

@@ -0,0 +1,40 @@
+# Challenge 1 - Write your own wc tool
+
+This challenge corresponds to the first part of the Coding Challenges series by John Crickett https://codingchallenges.fyi/challenges/challenge-wc.
+
+## Description
+
+The WC tool is written in `wc.ts` file and the `index.ts` is the command line version of the tool. The tool is used to count the number of words, lines, bytes and characters in a file/stdin.
+
+Check out [this](https://www.notion.so/mohitjain/1-Write-Your-Own-wc-Tool-b289bb2362c14778880029633b76033b) Notion page to understand how I approached this challenge.
+
+## Usage
+
+You can use `ts-node` to run the tool as follows:
+
+```bash
+npx ts-node index.ts [option] filename
+```
+
+The following options are supported:
+
+- `-w`: prints the number of words in the file
+- `-l`: prints the number of lines in the file
+- `-c`: prints the number of bytes in the file
+- `-m`: prints the number of characters in the file
+
+The tool can also be used in stdin mode as follows:
+
+```bash
+cat filename | npx ts-node index.ts [option]
+```
+
+## Run tests
+
+To run the tests for the WC tool, go to the root directory of this repository and run the following command:
+
+```bash
+npm run test tests/1/
+```
+
+The tests are located in the `tests/1/` directory. All the tests are made for **LINUX** environment only. If you want to run the tests in Windows environment, you can use the Git Bash terminal or Windows Subsystem for Linux (WSL).

src/10/README.md

@@ -0,0 +1,42 @@
+# Challenge 10 - Write Your Own uniq Tool
+
+This challenge corresponds to the tenth part of the Coding Challenges series by John Crickett https://codingchallenges.fyi/challenges/challenge-uniq.
+
+## Description
+
+The uniq tool is written in `uniq.ts` file and the `uniq.index.ts` is the command line version of the tool.
+
+## Usage
+
+You can use `ts-node` to run the tool as follows:
+
+```bash
+# Using input file
+npx ts-node uniq.index.ts [-option] <path/to/input-file>
+
+# Using standard input
+cat filename | npx ts-node uniq.index.ts [-option] -
+
+# Using output with input file
+npx ts-node uniq.index.ts [-option] <path/to/input-file> <path/to/output-file>
+
+# Using output with standard input
+cat filename | npx ts-node uniq.index.ts [-option] - <path/to/output-file>
+```
+
+The following options are supported:
+
+- `-c` or `--count`: prefix lines by the number of occurrences
+- `-d` or `--repeated`: only print duplicate lines
+- `-u`: only print unique lines
+- `-`: read from standard input
+
+## Run tests
+
+To run the tests for the uniq tool, go to the root directory of this repository and run the following command:
+
+```bash
+npm run test tests/10/
+```
+
+The tests are located in the `tests/10/` directory. All the tests are made for **LINUX** environment only. If you want to run the tests in Windows environment, you can use the Git Bash terminal or Windows Subsystem for Linux (WSL).

src/11/README.md

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+# Challenge 11 - Write Your Own Web Server
+
+This challenge corresponds to the eleventh part of the Coding Challenges series by John Crickett https://codingchallenges.fyi/challenges/challenge-webserver.
+
+## Description
+
+The web server API implementation is inspired from (express)[https://www.npmjs.com/package/express].
+The webserver is a basic implementation and a subpart of the express framework.
+It current handles only GET requests and supports responses and file responses.
+The webserver is able to handle the case when the callback to a GET function throws an error, by sending a 500 response.
+
+- `webserver.ts`: Contains the implementation of the web server, implemented using the `net` module of Node.js. It exposes `startServer`, `stopServer` and `get` methods to start, stop and handle GET requests respectively.
+- `index.ts`: A simple example of how to use the web server and serve a HTML file.
+- `request.ts`: A simple implementation of the request object that is passed to the callback of the `get` method.
+- `status_codes.ts`: Contains the supported status codes and their corresponding messages that are used in the response.
+
+## Usage
+
+You can directly import the HttpServer class from the `webserver.ts` file and use it as follows:
+
+```typescript
+import { HttpServer } from './webserver';
+
+// Create a new instance of the HttpServer class with
+const HOST = '127.0.0.1';
+const PORT = 8000;
+const debug = false;
+const webServer = new HttpServer(HOST, PORT, debug);
+
+// Handle GET requests
+webServer.get('/', (req) => {
+  res.send('Hello World!');
+});
+
+// Serve a HTML file
+webServer.get('/index.html', (req) => {
+  req.sendFile('path/to/index.html');
+});
+
+// Start the server
+webServer.startServer();
+```
+
+## Run tests
+
+To run the tests for the webserver, go to the root directory of this repository and run the following command:
+
+```bash
+npm run test tests/11/
+```
+
+The tests are located in the `tests/11/` directory.

src/13/README.md

@@ -0,0 +1,28 @@
+# Challenge 13 - Write Your Own diff Tool
+
+This challenge corresponds to the thirteenth part of the Coding Challenges series by John Crickett https://codingchallenges.fyi/challenges/challenge-diff.
+
+## Description
+
+The diff tool is written in `diff.ts` file and the `diff.index.ts` is the command line version of the tool.
+The diff tool is build using the Longest common subsequence (LCS) problem. We first find the LCS of a pair of strings and extend that to a pair of array of strings.
+While finding LCS we also store information about the insertions and deletions required to convert one string to another and use that information to print the differences between the two strings.
+
+## Usage
+
+You can use `ts-node` to run the tool as follows:
+
+```bash
+# Using input file
+npx ts-node diff.index.ts <file1> <file2>
+```
+
+## Run tests
+
+To run the tests for the diff tool, go to the root directory of this repository and run the following command:
+
+```bash
+npm run test tests/13/
+```
+
+The tests are located in the `tests/13/` directory.

src/14/README.md

@@ -0,0 +1,34 @@
+# Challenge 14 - Write Your Own Shell
+
+This challenge corresponds to the fourteenth part of the Coding Challenges series by John Crickett https://codingchallenges.fyi/challenges/challenge-shell.
+
+## Description
+
+As the name suggests, here we try to build a simple shell using the `child_process` module of Node.js.
+The shell supports all the commands (including piped commands) that are available in any standard LINUX shell.
+
+Apart from the builtin commands - `cd`, `pwd`, `exit`, `history` are executed by spawning a new process and passing all the relevant arguments provided by the user.
+
+## Usage
+
+You can use `ts-node` to run the tool as follows:
+
+```bash
+npx ts-node shell.ts
+```
+
+All the executed commands are stored in a file in the home directory of the user with the name `.ccsh_history`. You can then use the `history` command to see the previously executed commands.
+
+To exit the shell, use the `exit` command.
+
+The `pwd` and `cd` command support is implemented using the inbuilt `cwd()` and `chdir()` function exposed by the process module.
+
+## Run tests
+
+To run the tests for the shell tool, go to the root directory of this repository and run the following command:
+
+```bash
+npm run test tests/14/
+```
+
+The tests are located in the `tests/14/` directory. All the tests are made for **LINUX** environment only. If you want to run the tests in Windows environment, you can use the Git Bash terminal or Windows Subsystem for Linux (WSL).

src/15/README.md

@@ -0,0 +1,35 @@
+# Challenge 15 - Write Your Own cat Tool
+
+This challenge corresponds to the fifteenth part of the Coding Challenges series by John Crickett https://codingchallenges.fyi/challenges/challenge-cat.
+
+## Description
+
+The cat utility reads files sequentially, writing them to the standard output.
+The file operands are processed in command-line order. If file is a single dash (`-`) or absent, cat reads from the standard input.
+
+## Usage
+
+You can use `ts-node` to run the tool as follows:
+
+```bash
+# Using file
+npx ts-node cat.ts [-option] [filename]
+
+# Using stdin
+cat test.txt | npx ts-node cat.ts [-option]
+```
+
+The following options are supported:
+
+- `-n`: number the lines are they are printed out
+- `-b`: number the lines excluding blank lines
+
+## Run tests
+
+To run the tests for the cat tool, go to the root directory of this repository and run the following command:
+
+```bash
+npm run test tests/15/
+```
+
+The tests are located in the `tests/15/` directory. All the tests are made for **LINUX** environment only. If you want to run the tests in Windows environment, you can use the Git Bash terminal or Windows Subsystem for Linux (WSL).

src/16/README.md

@@ -0,0 +1,119 @@
+# Challenge 16 - Write Your Own IRC Client
+
+This challenge corresponds to the sixteenth part of the Coding Challenges series by John Crickett https://codingchallenges.fyi/challenges/challenge-irc.
+
+## Table of contents
+
+- [Description](#description)
+- [Usage](#usage)
+- [Run tests](#run-tests)
+- [TODOs](#todos)
+
+## Description
+
+The IRC client is written using the `net` module of Node.js.
+You can find more about the IRC protocol from https://datatracker.ietf.org/doc/html/rfc2812.
+
+- `command-types.ts`: Command types returned by server and supported by client
+- `parser.ts`: A parser class that parses the data sent by server into a more usable message interface
+- `types.ts`: All the interface definitions are present in this file
+- `utils.ts`: Utility functions used by IRC client
+- `irc-client.ts`: The main IRC Client login is written here.
+- `irc-client.index.ts`: A command line interface for IRC Client to interact with the server
+
+The IRC Client supports file based logging via [winston](https://www.npmjs.com/package/winston)
+
+The following commands are supported by the IRC Client:
+
+- JOIN
+- PART
+- NICK
+- PRIVMSG
+- QUIT
+
+## Usage
+
+To use the IRC Client command line interface, you can update the following variables present in `irc-client.index.ts` and use the `ts-node` command to start the client.
+
+```typescript
+const host = 'irc.freenode.net';
+const port = 6667;
+const nickName = 'MJ'; // Use you nickname
+const fullName = 'Mohit Jain'; // Use your full name
+const debug = true; // Enable winston logging
+```
+
+```bash
+npx ts-node irc-client.index.ts
+```
+
+The following commands are supported by the IRC Client:
+
+```bash
+# Connect to server
+client>connect
+
+# Join a channel
+client>/join <channel-name>
+
+# Leave a channel
+client>/part <channel-name>
+
+# Change your nickname
+client>/nick <new-nickname>
+
+# Send a message to a channel
+client>/privmsg <channel-name> <message>
+
+# Quit the IRC Client
+client>/quit
+```
+
+You can also use the IRC Client Class in your own code by importing it from `irc-client.ts`.
+
+```typescript
+import IRCClient from './irc-client';
+
+// logger is an instance of winston.Logger otherwise undefined
+const client = new IRCClient(host, port, nickName, fullName, debug, logger);
+
+// Connect the client to the server
+await client.connect();
+
+// Join a channel
+await client.join([{ channel: '#cc' }]);
+
+// Send message to a channel
+client.privateMessage('#cc', 'Hello World!');
+
+// Part a channel
+await client.part({ channels: ['#cc'], partMessage: 'Bye Bye' });
+
+// Update your nickname
+await client.nick('MJ');
+
+// Quit the server
+await client.quit('Bye Bye');
+
+// Get details about a channel
+const channelDetails = client.getChannelDetails('#cc');
+```
+
+You can add listeners to different command types supported by the IRC Client. The client exposes the `on()` method as mentioned in [types.ts](https://github.com/jainmohit2001/coding-challenges/blob/416a47f715fff82964bd8def81c26ab72cfe8978/src/16/types.ts#L189).
+
+## Run tests
+
+To run the tests for the IRC Client, go to the root directory of this repository and run the following command:
+
+```bash
+npm run test tests/16/
+```
+
+The tests are located in the `tests/16/` directory.
+
+## TODOs
+
+- [ ] Add support for multiple channels for JOIN and PART commands.
+- [ ] Add command line option support for `irc-client.index.ts`.
+- [ ] Separate the command handling from the main IRC client code into more a structured and scalable format.
+- [ ] Improve tests.