JavaScript Arrow Functions vs JavaScript Functions
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When to Use Each
Use traditional functions
- When you need to use function hoisting (arrow functions are not hoisted).
- If you need to access the
arguments
object. - When using methods that will be added to an object's prototype.
- If you need a dynamic context (
this
), such as in event handlers.
Use arrow functions
- For shorter syntax in functional programming scenarios.
- When working with higher-order functions that expect a function callback.
- In cases where you want to retain the lexical
this
scope (e.g., in nested functions or event handlers). - For single-line functions with implicit returns.
Differences
Syntax
Arrow functions provide a shorter syntax. They are written with an arrow rather than the function
keyword.
Traditional function
function add(a, b) {
return a + b
}
Arrow function:
const add = (a, b) => a + b;
this
Binding
One of the most significant differences is how this
is handled. In traditional functions, this
is dynamic and can change depending on the context in which the function is called. In arrow functions, this
is lexically scoped, meaning it uses this
from the surrounding code where the function is defined.
No Binding of arguments
Arrow functions do not have their own arguments
object. Instead, they access the arguments
object of the closest non-arrow parent function.
Cannot be used as Constructors
Arrow functions cannot be used as constructor functions. They cannot be called with new
.
No Duplicate Named Parameters
Traditional functions allow duplicate named parameters in non-strict mode, while arrow functions do not, regardless of strict mode.
No prototype
Property
Arrow functions do not have a prototype
property.