url prod - TypeScript

TypeScript is a popular programming language that is a superset of JavaScript. It adds static type checking, classes, interfaces, and other features to JavaScript, making it more powerful and easier to use. In this article, we'll explore how to use TypeScript to create URL processing code for production environments.

Setting up TypeScript

To use TypeScript, you'll need to install it first. You can install it globally using npm by running:

npm install -g typescript

Once TypeScript is installed, you can create a new TypeScript project by running:

mkdir my-project
cd my-project
npm init -y

Then, create a new tsconfig.json file in the root of your project:

{
  "compilerOptions": {
    "module": "commonjs",
    "target": "es6",
    "sourceMap": true,
    "outDir": "dist",
    "strict": true,
    "esModuleInterop": true
  },
  "include": ["src/**/*"]
}

This tsconfig.json file tells TypeScript to compile your code into commonjs modules, target es6 syntax, generate source maps, output the compiled code into a dist directory, enable strict type-checking, and allow for interop with CommonJS modules.

Writing URL processing code

Now that we have TypeScript set up, let's start writing some code. We'll create a simple URL parser that takes a URL string and returns an object with properties for the protocol, host, port, path, and query string.

interface UrlParts {
  protocol: string;
  host: string;
  port: string | null;
  path: string;
  query: { [key: string]: string };
}

function parseUrl(urlString: string): UrlParts {
  const url = new URL(urlString);
  const query = Object.fromEntries(url.searchParams.entries());
  return {
    protocol: url.protocol,
    host: url.hostname,
    port: url.port !== "" ? url.port : null,
    path: url.pathname,
    query,
  };
}

In this code, we define an interface UrlParts that describes the shape of the returned object. We then define a function parseUrl that takes a urlString parameter and returns an object with the properties defined by the UrlParts interface.

To parse the URL, we first create a new URL object using the urlString parameter. We then use various properties of the URL object to populate the UrlParts object. We convert the query parameters into a plain object using the Object.fromEntries() method introduced in ES2019.

Building and running the code

To build the TypeScript code, run:

tsc

This will compile the TypeScript code into JavaScript and output it into the dist directory as defined in the tsconfig.json file.

To test the code, create a test.js file in the root of your project with the following code:

const { parseUrl } = require('./dist/url');

const url = 'https://www.example.com:8080/path/to/something?foo=bar&baz=qux';
const parts = parseUrl(url);
console.log(parts);

This code imports the parseUrl function from the compiled url.js module and uses it to parse a sample URL. Running node test.js should output the following:

{
  protocol: 'https:',
  host: 'www.example.com',
  port: '8080',
  path: '/path/to/something',
  query: { foo: 'bar', baz: 'qux' }
}

Conclusion

TypeScript is a powerful language that adds type checking and other features to JavaScript. By using TypeScript in a production environment, we can catch errors early and benefit from better code organization and readability. In this article, we explored how to use TypeScript to create a basic URL parser that illustrates some of the language's key features.