javascript - CoffeeScript - 数组过滤不起作用

Question

我试图获取一个仅包含具有背景图像属性的元素的数组，但是，我的代码无法正常工作，我不确定出了什么问题。

elements = document.getElementsByTagName("*")
[].filter.call elements, (el) =>
  if el.currentStyle
    return el.currentStyle['backgroundImage'] isnt 'none'
  else if window.getComputedStyle
    return document.defaultView.getComputedStyle(el,null).getPropertyValue('background-image') isnt 'none'

Answer 1

根据javascript documentation ,

The filter() method creates a new array with all elements that pass the test implemented by the provided function.

因此，您需要在使用之前存储过滤后的数组:

elements = document.getElementsByTagName("*")
filteredElements = [].filter.call elements, (el) =>
  if el.currentStyle
    return el.currentStyle['backgroundImage'] isnt 'none'
  else if window.getComputedStyle
    return document.defaultView.getComputedStyle(el,null).getPropertyValue('background-image') isnt 'none'

// filteredElements is your new array with the filtered elements.