ES6 Modules: What\'s the Difference Between `export const` and `export default`?

Exporting Constructs in ES6: Understanding export const and export default

When working with modules in ES6, developers often encounter the concepts of export const and export default. Understanding the distinctions between these two export methods is crucial for architecting code effectively.

Named Exports (export const)

export const is utilized for named exports. It exports constant declarations, allowing multiple named exports within a single file. To import named exports, developers employ braces in the import statement:

import { myConst1, myConst2 } from './myModule.js';

Default Exports (export default)

export default exports a default item, which can only exist once per file. When importing default exports, developers specify a custom name:

import MyDefaultExport from './myModule.js';

Key Differences

Apart from the syntactic differences in import syntax, the main distinction between named and default exports lies in their singularity. Named exports can have multiple exports, while default exports are restricted to one per file.

Use Cases

Named Exports:

• Exporting multiple functions, variables, or classes with specific names
• Providing flexibility to import only the desired constructs

Default Exports:

• Exporting a primary function, object, or class as the main interface for the module
• Encapsulating the core functionality of the module into a single export

Namespace Import

Additionally, ES6 provides the import * as syntax to import all exports from a module into a namespace object:

import * as MyModule from './myModule.js';

Conclusion

export const and export default serve distinct purposes in ES6 modules. Understanding the differences and use cases for each allows developers to organize their code effectively, promote reusability, and maintain a clean and modular architecture.

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