Arrow functions (also known as fat arrow functions) were introduced in ECMAScript 6 (ES6) and provide a more concise syntax compared to regular functions in JavaScript. Here are some key differences between the two:
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Syntax:
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Regular function: Declared using the
functionkeyword followed by a name and parameters enclosed in parentheses. For example:function regularFunction(a, b) { return a + b; } -
Arrow function: Use a shorter syntax using the => syntax without the function keyword, often without the need for curly braces for single expressions. For example:
let arrowFunction = (a, b) => a + b;
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Regular function: Declared using the
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thisBinding:-
Regular functions have their own
thiscontext, which is dynamically scoped and defined each time the function is called. The value ofthisdepends on how the function is invoked (withcall(),apply(), or context-based calling). -
Arrow functions inherit the
thiscontext from the surrounding code (lexical scoping). They don’t have their ownthiscontext; instead, they use thethisvalue from the enclosing execution context.
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Regular functions have their own
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Arguments Object:
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Regular functions have their own
argumentsobject, which contains all the arguments passed to the function. -
Arrow functions do not have their own
argumentsobject. Instead, they inherit the arguments object from their containing scope.
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Regular functions have their own
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newkeyword andprototype:-
Regular functions can be used as constructor functions with the
newkeyword and can have aprototypeproperty. -
Arrow functions cannot be used as constructors and do not have a
prototypeproperty. Trying to usenewwith an arrow function will result in a TypeError.
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Regular functions can be used as constructor functions with the
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Usage in Object Methods:
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Regular functions are useful in defining object methods as they allow access to the object via
this. -
Arrow functions are often used when you want to preserve the context of
thisfrom the surrounding code, especially in callback functions or when defining functions within other functions.
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Regular functions are useful in defining object methods as they allow access to the object via
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argumentsObject: -
Regular functions have their own
argumentsobject that contains all arguments passed to the function. -
Arrow functions do not have their own
argumentsobject. They inherit theargumentsobject from their parent scope. -
Implicit Return:
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Arrow functions, when written as a single expression without curly braces, have an implicit return, automatically returning the value without using the
returnkeyword. -
Regular functions require explicit use of the return keyword to
returna value.
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Arrow functions, when written as a single expression without curly braces, have an implicit return, automatically returning the value without using the
Arrow functions offer a concise syntax and lexically scoped this but lack certain features, such as the arguments object or the ability to be used as constructors. Understanding these differences helps in choosing the appropriate function syntax for different scenarios in JavaScript programming.