What's a typical use case for anonymous functions in JavaScript?

An anonymous function in JavaScript is a function that does not have any name associated with it. They are typically used as arguments to other functions or assigned to variables.

const arr = [-1, 0, 5, 6];

// The filter method is passed an anonymous function.
arr.filter((x) => x > 1); // [5, 6]

They are often used as arguments to other functions, known as higher-order functions, which can take functions as input and return a function as output. Anonymous functions can access variables from the outer scope, a concept known as closures, allowing them to "close over" and remember the environment in which they were created.

// Encapsulating Code
(function () {
  // Some code here.
})();

// Callbacks
setTimeout(function () {
  console.log("Hello world!");
}, 1000);

// Functional programming constructs
const arr = [1, 2, 3];
const double = arr.map(function (el) {
  return el * 2;
});
console.log(double); // [2, 4, 6]

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