ReasonJun

event obj // The event object contains event information that has occurred in the target. const parentEl = document.querySelector('.parent'); parentEl.addEventListener('click', (event) => { console.log(event.target, event.currentTarget); // The target of the (selected) event, the target where the event is registered console.log(event); // You can get information about an event that has occurred...

delegation // event delegation // If you need to handle events on multiple elements in a similar pattern, // You can use the event delegation pattern, controlled by a single ancestor element. const parentEl = document.querySelector('.parent'); const childEls = document.querySelectorAll('.child'); // Event registration for all targets! childEls.forEach((el) => { el.addEventListener('click', (even..

add / remove //? .addEventListener() // Registers to listen for events on the target. // When an event specified in the target occurs, the specified function is called. const parentEl = document.querySelector('.parent'); const childEl = document.querySelector('.child'); parentEl.addEventListener('cilck', () => { console.log('Parent'); }); childEl.addEventListener('cilck', () => { console.log('Ch..

toReserved / toSorted / toSpliced (copy, no mutate) const x = [1, 2, 3]; const y = x.toReversed(); y.push(0) const arr = [1,3,2]; const sorted = arr.toSorted(); console.log(arr); // [1, 3, 2] console.log(sorted); // [1, 2, 3] const a = [ "a", "b", "c", "d"] const newArray = a.toSpliced(1,2) // ['a', 'b'] with const x = ["a", "b", "c", "x"] x[3] = "d" console.log(x) // ["a", "b", "c", "d"] const ..

In JavaScript, there are several array methods that do not mutate the original array. Instead of modifying the array in place, they return a new array with the desired modifications. Here are some commonly used array methods that have non-mutating behavior: concat: The concat() method is used to merge two or more arrays and returns a new array without modifying the existing arrays. const array1 ..

In JavaScript, there are several array methods that can mutate the original array, meaning they modify the array directly instead of creating a new array. These methods allow you to add, remove, or modify elements within an array. Here are some commonly used array methods that have mutating behavior: 1. push: The push() method adds one or more elements to the end of an array and returns the new ..