Named Export vs Default Export in JavaScript: Key Differences and Usage

In JavaScript, named exports allow you to export multiple values by name from a module, while default export lets you export a single value as the main export. Named exports require importing with the exact exported names, whereas default exports can be imported with any name.

Quick Comparison

Here is a quick side-by-side comparison of named exports and default exports in JavaScript modules.

Aspect	Named Export	Default Export
Number of exports per module	Multiple allowed	Only one allowed
Import syntax	Must use exact exported names inside curly braces	Can use any name without curly braces
Use case	Export multiple utilities or constants	Export a single main value or function
Renaming on import	Possible with aliasing	Always possible since import name is flexible
Syntax example	export const foo = 1;	export default function() {}

Key Differences

Named exports let you export several variables, functions, or classes by their names. When importing, you must use the exact exported names inside curly braces, but you can rename them using as. This helps keep code clear and allows selective imports.

Default export allows exporting a single value as the main export of a module. When importing, you do not use curly braces and can choose any name for the imported value. This is useful when a module has one primary thing to export.

Also, a module can have multiple named exports but only one default export. Mixing both in the same module is allowed but should be done carefully to avoid confusion.

Code Comparison

Example of using named exports to export multiple functions from a module.

javascript

export function greet() {
  return 'Hello';
}

export function farewell() {
  return 'Goodbye';
}

Default Export Equivalent

Example of using default export to export a single function from a module.

javascript

export default function greet() {
  return 'Hello';
}

When to Use Which

Choose named exports when your module has multiple utilities or values that users might want to import selectively. It keeps imports clear and explicit.

Choose default export when your module mainly exports one primary thing, like a single function or class, making imports simpler and more flexible in naming.

For larger projects, named exports improve maintainability by making dependencies explicit, while default exports are great for simple modules or libraries.

Key Takeaways

Named exports allow multiple exports and require exact import names inside curly braces.

Default export allows only one export per module and can be imported with any name without braces.

Use named exports for multiple utilities and default export for a single main value.

You can rename named exports on import using aliasing with 'as'.

Mixing named and default exports in one module is possible but should be done carefully.