javascript 数组差值计算

Question

我有个数组
数组内的原始值是[1,4,7,9,20,45,67,89,97],依次顺序排列
我现在想得到，后一个元素，-前一个元素的，差值，
用JavaScript怎么写恩

Answer 1

[code="java"]
function mergeToRanges(ary) {
var acc = null
var last = null
for (var i = 0; i < ary.length; i++) {
var e = ary[i]
if (!acc) {
last = [e]
acc = [last]
} else if (1 == last.length && last[0] + 1 == e) {
last = [last[0], e]
acc[acc.length-1] = last
} else if (2 == last.length && last[1] + 1 == e) {
last = [last[0], e]
acc[acc.length-1] = last
} else {
last = [e]
acc = acc.concat(last)
}
}
return acc
}

mergeToRanges([1,2,3,6,9,20,21,34,45,67,68]).join('\n')
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