学ぶ Arrow Functions | Modern and Advanced Function Patterns

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Arrow functions offer a modern, concise way to write functions in JavaScript. They are especially useful for short, simple tasks, such as working with arrays or creating small utility functions.

The syntax for arrow functions is more compact than traditional function expressions. To define an arrow function, you use the => syntax.

For example, a function that takes a number and returns its double can be written as:

const double = (n) => n * 2;

If a function has only one parameter, you can omit the parentheses:

const double = n => n * 2;

If the function body is a single expression, the result is returned automatically, so the return keyword is not needed.

const add = (a, b) => a + b;


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// Regular function
function doubleArray1(arr) {
  return arr.map(function (num) {
    return num * 2;
  });
}

// Usage:
console.log(doubleArray1([1, 2, 3])); // [2, 4, 6]

// Arrow function
const doubleArray2 = (arr) => arr.map((num) => num * 2);

// Usage:
console.log(doubleArray2([1, 2, 3])); // [2, 4, 6]

Arrow functions provide a shorter syntax for writing functions;
Parentheses can be omitted when there is only one parameter;
Single-expression functions return values automatically;
Arrow functions are best used for small, simple operations.

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