Javascript：一次在多個數組上使用 foreach

Question

我有 2 個arrays或更可能的NodeLists ，

const mainSlides = document.querySelectorAll('.mainSlides')
const thumbSlides = document.querySelectorAll('.thumbSlides')

目前我正在像這樣迭代它們：

mainSlides.forEach(slide => {
    slide.style.backgroundColor = `red`
})

thumbSlides.forEach(slide => {
    slide.style.backgroundColor = `red`
})

由於它們都設置了相同的屬性，即； background-color:red; , 是否有一種速記方式可以同時遍歷兩個節點列表？

 const mainSlides = document.querySelectorAll('.mainSlides') const thumbSlides = document.querySelectorAll('.thumbSlides') mainSlides.forEach(slide => { slide.style.backgroundColor = `red` }) thumbSlides.forEach(slide => { // slide.style.backgroundColor = `red` })

 <div class="holder"> <div class="mainSlides"> some mainSlides </div> <div class="mainSlides"> some mainSlides </div> <div class="mainSlides"> some mainSlides </div> <div class="mainSlides"> some mainSlides </div> </div> <div class="holder"> <div class="thumbSlides"> some mainSlides </div> <div class="thumbSlides"> some mainSlides </div> <div class="thumbSlides"> some mainSlides </div> <div class="thumbSlides"> some mainSlides </div> </div>

Answer 1

是的，您可以在一個選擇器中同時選擇兩者：

const mainAndThumbSlides = document.querySelectorAll('.mainSlides,.thumbSlides')

Answer 2

您可以像這樣同時選擇mainSlides和thumbSlides ：

const allSlides = document.querySelectorAll('.mainSlides, .thumbSlides');

或者，如果您不想將它們一起選擇（例如，如果您想進一步單獨使用它們）而只想將它們一起用於此特定操作：

const allSlides = [...mainSlides, ...thumbSlides];
allSlides.forEach(slide => {
    slide.style.backgroundColor = 'red';
})

Answer 3

您的代碼已經可以在我的瀏覽器中運行了，但無論如何這可能會對您有所幫助：

這是訪問：

mainSlides.forEach( (item, index, array) => {
  array[index] = newValue;
})

看看代碼片段：

 const mainSlides = document.querySelectorAll('.mainSlides') const thumbSlides = document.querySelectorAll('.thumbSlides') mainSlides.forEach( (slide, index, mainSlidesReference) => { console.log("This is only for collecting variable => ", slide.style.backgroundColor) // You can named who ever you want - importanty it is third argument // Ussually called simple `array` // I give him mainSlidesReference to make clear mainSlidesReference[index].style.backgroundColor = `red`; }) thumbSlides.forEach( (slide, index, mainSlidesReference) => { console.log("This is only for collecting variable => ", slide.style.backgroundColor) // You can named who ever you want - importanty it is third argument // Ussually called simple `array` // I give him mainSlidesReference to make clear mainSlidesReference[index].style.backgroundColor = `red`; })

 .holder { display:flex; } .mainSlides { background-color: black; } .thumbSlides { background-color: black; }

 <div class="holder"> <div class="mainSlides"> some mainSlides </div> <div class="mainSlides"> some mainSlides </div> <div class="mainSlides"> some mainSlides </div> <div class="mainSlides"> some mainSlides </div> </div> <div class="holder"> <div class="thumbSlides"> some mainSlides </div> <div class="thumbSlides"> some mainSlides </div> <div class="thumbSlides"> some mainSlides </div> <div class="thumbSlides"> some mainSlides </div> </div>