JS Array forEach()

除了 for() loop 之外, 另一個選擇.forEach():

let data = [1, 2, 3, 4, 5];
let sum = 0;
data.forEach(function(value){
  sum += value;
});
sum; // 15

這個 forEach() 似乎變成主要的用法, 在 bootstrap 的範例裡, 非常地常見到:
https://getbootstrap.com/docs/5.3/components/scrollspy/

Non-visible elements 

Target elements that aren’t visible will be ignored and their corresponding nav items won’t receive an .active class. Scrollspy instances initialized in a non-visible wrapper will ignore all target elements. Use the refresh method to check for observable elements once the wrapper becomes visible.

document.querySelectorAll('#nav-tab>[data-bs-toggle="tab"]').forEach(el => {
  el.addEventListener('shown.bs.tab', () => {
    const target = el.getAttribute('data-bs-target')
    const scrollElem = document.querySelector(`${target} [data-bs-spy="scroll"]`)
    bootstrap.ScrollSpy.getOrCreateInstance(scrollElem).refresh()
  })
})