How does JS compare two arrays with exactly the same elements?
JavaScript can not directly use = = or = = = To determine whether two arrays are equal, whether equal or congruent, the following two lines of JS code will return false
<script type= "Text/javascript" > alert ([]= =[]); Alert ([]= = =[]); </script>
To determine whether the two arrays in JS are the same, you need to convert the array to a string before comparing it. The following two lines of code will return true
<script type= "Text/javascript" > alert ([].tostring ()= = [].tostring ()]; Alert ([].tostring ()= = = =[].tostring ()]); </script>
JS to compare two arrays have the same element, that is, two arrays all elements are the same, but the order of the elements is not necessarily consistent. You only need to sort the array first, and then compare the two arrays for equality.
Try comparing the following two lines of code:
<script type= "Text/javascript" > alert ([1,2,3].tostring () = = [3,2,1].tostring ()); Alert ([1,2,3].sort (). ToString () = = [3,2,1].sort (). ToString ()); </script>
How does JavaScript compare two arrays?