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Using TypeScript Import Syntax with Default Exports

TypeScript is a statically typed, multi-paradigm programming language developed by Microsoft. It is designed to help developers catch errors early and improve code maintainability, thus making it a popular choice for large-scale JavaScript applications. One of the key features of TypeScript is its support for ES6 modules, which allows developers to organize their code into reusable modules and import them as needed.

Default Exports in TypeScript

In TypeScript, a default export is a way to export a single value or function from a module, making it easily importable by other modules. When a module has a default export, it can be imported using the import syntax without specifying the exact name of the export.

Example of a Default Export


// myModule.ts
export default function add(a: number, b: number) {
  return a + b;
}

Importing a Default Export in TypeScript

To import a default export in TypeScript, you can use the import syntax with the default keyword. Here's an example:


// main.ts
import add from './myModule';

console.log(add(2, 3)); // Outputs: 5

In this example, the add function is imported from the myModule module and assigned to a variable named add. The default keyword is not required when importing a default export, but it can be used to make the code more readable.

Importing a Default Export with a Different Name

If you want to import a default export with a different name, you can use the as keyword. Here's an example:


// main.ts
import myAdd from './myModule';

console.log(myAdd(2, 3)); // Outputs: 5

In this example, the add function is imported from the myModule module and assigned to a variable named myAdd.

Importing a Default Export with Other Exports

If a module has both a default export and other named exports, you can import them together using the import syntax with the default keyword and the named exports. Here's an example:


// myModule.ts
export default function add(a: number, b: number) {
  return a + b;
}

export function subtract(a: number, b: number) {
  return a - b;
}


// main.ts
import add, { subtract } from './myModule';

console.log(add(2, 3)); // Outputs: 5
console.log(subtract(5, 3)); // Outputs: 2

In this example, the add function is imported as the default export, and the subtract function is imported as a named export.

Conclusion

In conclusion, using the TypeScript import syntax with default exports is a convenient way to import single values or functions from modules. By using the default keyword and the import syntax, you can easily import default exports and use them in your code. Additionally, you can import default exports with other named exports, making it easy to organize your code into reusable modules.

Frequently Asked Questions

Q: What is a default export in TypeScript?

A: A default export is a way to export a single value or function from a module, making it easily importable by other modules.

Q: How do I import a default export in TypeScript?

A: You can import a default export using the import syntax with the default keyword. For example: import add from './myModule';

Q: Can I import a default export with a different name?

A: Yes, you can import a default export with a different name using the as keyword. For example: import myAdd from './myModule';

Q: Can I import a default export with other exports?

A: Yes, you can import a default export with other named exports using the import syntax with the default keyword and the named exports. For example: import add, { subtract } from './myModule';

Q: What is the difference between a default export and a named export?

A: A default export is a single value or function that is exported from a module, while a named export is a value or function that is exported with a specific name. Named exports can be imported using the import syntax with the exact name of the export.

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