javascript实现获取磁盘中a文件与b文件的相对路径

var aPath = 'C:/programfiles/game/a'
        var bPath = 'C:/workspace/QQ/game/b'
        function positivePath(a, b) {
            var aArr = a.split('/')
            var bArr = b.split('/')
            for (var i = 0; i < aArr.length - 2; i++) {
                if (bArr[i] != aArr[i]) {
                    bArr.splice(0,i)
                    return '../'.repeat(aArr.length - i) + bArr.join('/')
                }
            }
        }
        console.log(positivePath(aPath, bPath))