姓名隐藏星号，隐藏中间文字

function formatName (name) {
    var newStr
    if (name.length === 2) {
        newStr = name.substr(0,1) + '*'
    } else if (name.length > 2) {
        var char = ''
        for (var i = 0,len = name.length - 2;i < len;i++) {
            char += '*'
        }
        newStr = name.substr(0,1) + char + name.substr(-1,1)
    } else {
        newStr = name
    }
    return newStr
}
console.log(formatName('王大'))
console.log(formatName('王大大'))
console.log(formatName('王大对对对大家'))