a - what is a high-order function higher-order functions (HOFs) are functions that take other functions as arguments or return them as results HOFs are a core concept in functional programming and allow for more flexible and reusable code. key concepts related to higher-order functions Functions as Arguments → You can pass a function to another function. Returning Functions → A function can return another function. Common HOFs in JavaScript: map(), filter(), reduce(), forEach(), some(), every() Callback Functions → Functions passed as arguments to other functions Common in asynchronous operations Closures → HOFs often create closures, where inner functions can access outer function's scope Currying → Transforming a function with multiple arguments into a sequence of functions with one argument each Function Composition → Combining multiple functions to create more complex ones Higher-order Components (HOCs) in React → Functions that take a component and return a new component Partial Application → Applying some arguments to a function to produce another function with fewer arguments Memoization → Storing the results of expensive function calls and returning cached results when the same inputs occur again
b - high-order function examples Part 1 Functions as Arguments A function can take another function as an argument. This is a common pattern used in array methods like map(), filter(), and reduce() Returning Functions A function can also return another function. This is useful for creating function factories or implementing currying. Common Higher-Order Functions map() Transforms each element in an array and returns a new array. filter() Creates a new array with elements that pass a test function. reduce() Reduces an array to a single value. Callback Functions Functions passed as arguments to other functions are called callback functions. They are commonly used in asynchronous operations. Closures HOFs often create closures, where inner functions can access outer function's scope even after the outer function has finished executing.
c - high-order function examples Part 2 Currying Currying is a technique where a function with multiple arguments is transformed into a sequence of functions, each with one argument. Function Composition Function composition is the act of combining multiple functions to create more complex ones. Higher-Order Components (HOCs) in React In React, HOCs are functions that take a component and return a new component with additional functionality. Partial Application Partial application is a technique where some arguments are applied to a function to produce another function with fewer arguments. Memoization Memoization is a technique for storing the results of expensive function calls and returning cached results when the same inputs occur again. Higher-order functions are a powerful feature of JavaScript that enable more flexible, reusable, and expressive code. By understanding and utilizing HOFs, you can write cleaner, more modular, and maintainable code.