Export const vs. export default: When to Use Which ES6 Module Export?

Exporting with export const vs. export default in ES6

In JavaScript ES6 modules, there are two primary ways to export values, namely export const and export default. These export mechanisms offer distinct features and use cases.

Named Exports (export const)

export const is used to export named constants. This allows you to export multiple specific values from a module, each with its own unique identifier. To import such exports, you specify the desired variable names within curly braces:

// Exporting
export const myItem = 'Exported value';

// Importing
import { myItem } from 'myItem';

Default Exports (export default)

export default is used to export a default value. This can only be done once per module. When importing a default export, you can give it any alias you wish:

// Exporting
export default { name: 'John Doe', age: 30 };

// Importing
import MyDefaultExport from 'myItem';

Use Cases

The following list provides some general guidelines for choosing between export const and export default:

• Named exports:

  • Use export const when you need to export multiple specific values from a module.

• Default exports:

  • Use export default when you want to export a single, primary value from a module.
  • Use export default when you need to support legacy code that expects a specific import (e.g., importing react-dom as the default export).

Additional Features

In addition to their core functionality, export const and export default offer several additional features:

• Namespace imports: You can use import * as to import all exports from a module as an object.
• Partial imports: You can mix and match named and default imports in the same statement.
• Renaming imports: You can rename imported values using the as keyword.

Remember that export default is a special case of named exports with the name "default." This allows for some flexibility in how you import the default value.

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