JS array delete splice 区别

Delete in this case will only set the element as undefined:

> myArray =['a','b','c','d']

>delete myArray[0]

true

> myArray

 [undefined,"b","c","d"]

Splice actually removes the element from the array:

> myArray =['a','b','c','d']

>myArray.splice(0,1)

true

> myArray

 ["b","c","d"]