In TypeScript, you can use module exports to make your code more modular and reusable. Module exports allow you to define which parts of a file can be accessed by other files in your project.

Exporting a Single Value

To export a single value from a TypeScript module, you can use the export keyword followed by the value you want to export. Here’s an example:

// mathUtils.ts

export function add(a: number, b: number): number {
    return a + b;
}

export const PI = 3.14159;

In the above example, we export a function add and a constant PI from the mathUtils.ts file. These exports can now be used in other files by importing them.

Exporting Multiple Values

If you have multiple values that you want to export from a module, you can use the export keyword before each value declaration. Here’s an example:

// utils.ts

export function capitalize(str: string): string {
    return str.charAt(0).toUpperCase() + str.slice(1);
}

export function reverse(str: string): string {
    return str.split("").reverse().join("");
}

In the above example, we export two functions capitalize and reverse from the utils.ts file. These functions can be imported and used in other files.

Default Export

In addition to named exports, TypeScript also supports default exports. A default export is used when you want to export a single value as the default export of a module. Here’s an example:

// logger.ts

export default function log(message: string): void {
    console.log(message);
}

In the above example, we export a single function log as the default export of the logger.ts file. When importing a default export, you can give it any name you want.

Importing Exported Values

To use exported values from a module in another file, you need to import them. Here’s an example of importing the previously exported functions:

// app.ts

import { add, PI } from './mathUtils';
import { capitalize, reverse } from './utils';
import log from './logger';

console.log(add(2, 3)); // Output: 5
console.log(PI); // Output: 3.14159
console.log(capitalize('hello')); // Output: Hello
console.log(reverse('world')); // Output: dlrow
log('Hello, logger!'); // Output: Hello, logger!

In the above example, we import the add function and the PI constant from the mathUtils.ts file, the capitalize and reverse functions from the utils.ts file, and the log function as the default export from the logger.ts file.

By using module exports in TypeScript, you can create more organized and modular codebases, making it easier to reuse and maintain your code.

#TypeScript #ModuleExports