方法1:
function truncate(arr) { var newArr = arr.slice() newArr.splice(newArr.length-1,1) return newArr }
方法2:
function truncate(arr) { return arr.slice(0,arr.length-1) }
function truncate(arr) { var newArr = arr.slice() newArr.splice(newArr.length-1,1) return newArr }
function truncate(arr) { return arr.slice(0,arr.length-1) }