QUESTION: What are debounce and throttle?

The debounce and throttle techniques are fundamental performance optimization methods in JavaScript. They allow you to effectively control the frequency of function calls when frequent events occur, such as page scrolling, window resizing, or user text input.

The debounce method works on the principle of delayed execution. It guarantees that the function will be called only after the stream of events stops for a certain pause specified by the developer.

If a new event occurs during this pause, the timer resets from the beginning. This is ideal for autocomplete search bars or handling the completion of browser window resizing, when there is no point in performing heavy computations on every single pixel of change.

In turn, the throttle method solves the opposite problem. It limits the execution of a function so that it is called no more than once in a given time interval, for example, exactly once every one hundred milliseconds.

This is indispensable for events such as page scrolling scroll or mouse movement mousemove, when smooth interface response is needed, but a continuous stream of calls would clog the main processor thread. Implementing these patterns from scratch every time is not required, as professional developers usually use ready-made, proven solutions from popular libraries such as lodash.debounce and lodash.throttle.