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

Comparing export const and export default in ES6

In ES6, exporting and importing modules allows for code organization and reusability. Two common export syntaxes are export const and export default. While both serve the purpose of exporting values, they have distinct characteristics and use cases.

export const (Named Export)

export const exports a named variable or constant, allowing multiple named exports from a single file. To import named exports, specific curly-bracketed names must be specified:

// export named variables
export const myItem1 = "item1";
export const myItem2 = "item2";

// import named exports
import { myItem1, myItem2 } from "myModule";

export default (Default Export)

export default exports a single default value from a file. When importing the default export, a custom name can be assigned:

// export default value
export default "Default Value";

// import default export as custom name
import CustomDefaultName from "myModule";

Usage and Differences

The primary difference between export const and export default lies in their usage scenarios:

• When to use export const: When exporting multiple named values from a file, such as constants, classes, or functions.
• When to use export default: When exporting a single default value or the main functionality of a module, such as a component or utility.

Namespace Import

In addition to named and default imports, it's possible to import all exports from a file using the namespace import syntax:

import * as myModule from "myModule";

This imports all exported values into the myModule object, allowing access to named exports using dot notation.

Notes

• Default exports can be named during import using curly braces: { default as myDefault }.
• Despite the name "default", default exports are still named exports and can be imported with specific names.
• Default exports are slightly more concise in syntax but may not always be appropriate for every use case.

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