függvénykifejezésekként

Függvénykifejezésként translates to "as a function expression" in English and refers to a way of defining functions in programming languages, particularly in JavaScript. Unlike a function declaration, a function expression creates a function and assigns it to a variable. This means the function can be treated like any other value, such as a number or a string.

A common form of a function expression is using the `function` keyword followed by the function's name (optional), parameters, and body. For example: `const myFunction = function(parameter1, parameter2) { // function body };`. The function is then accessible through the `myFunction` variable.

Another type is an anonymous function expression, where the function name is omitted. These are often used for callbacks or immediately invoked function expressions (IIFEs). For instance: `setTimeout(function() { console.log('Hello'); }, 1000);`.

Function expressions offer flexibility. Because they are assigned to variables, they can be passed as arguments to other functions, returned from functions, or assigned to different variables. This is a fundamental concept in functional programming paradigms.

The key distinction from function declarations is hoisting. Function declarations are hoisted to the top of their scope, meaning they can be called before they are defined in the code. Function expressions, however, are not fully hoisted; only the variable declaration is hoisted, not the function assignment itself. Therefore, calling a function expression before its definition will result in an error. This difference in behavior is crucial for understanding code execution flow.