使用 TypeScript 检查一个人今年是否达到特定年龄 (JavaScript)

Question

我认为我的问题很容易解决，但我就是无法掌握它的窍门。我想要一个函数，它检查此人在当年是否年满 18 岁，但此人在检查时不必已经 18 岁。

示例： "Mike turns 18 next week"。所以他今天还是 17 岁，但函数应该 return 为真，因为他今年将满 18 岁。如果 Mike 明年年满 18 岁，该函数应该 return false。

这是我目前得到的，但是这个函数只检查这个人是否已经 18 岁。

dateString = "2000-02-23" // person is 17 but turns 18 next week, so function should return true
otherDateString = "2001-01-13" //person is also 17, but function should return false, because this person just turnt 17 this year and will turn 18 next year

calculateAge(dateString) {
    let birthday = new Date(dateString);
    let ageDifMs = Date.now() - birthday.getTime();
    let ageDate = new Date(ageDifMs); // milliseconds from epoch
    let age = Math.abs(ageDate.getFullYear() - 1970);
    console.log(age);
    if (age>=18)
      return true;
  }

我如何才能将功能更改为只检查此人今年是否年满 18 岁，而不管此人是否仍未满 17 岁？

Answer 1

这样做应该很容易：

dateString = "2000-02-23" // person is 17 but turns 18 next week, so function should return true
otherDateString = "2001-01-13" //person is also 17, but function should return false, because this person just turnt 17 this year and will turn 18 next year

function calculateAge(dateString) {
    let birthday = new Date(dateString);
    let now = new Date();
    return now.getYear() - birthday.getYear() >= 18;
}

Answer 2

您不需要将输入的日期字符串解析为日期，事实上，如果您不这样做会更好。参见 Why does Date.parse give incorrect results?

您需要做的就是从日期字符串中获取年份，然后从当前年份中减去它。如果结果是 18，那么他们今年就满 18 岁了：

function eighteenThisYear(s) {
  return new Date().getFullYear() - s.split(/\D/)[0] == 18;
}

['1999-12-31','2000-02-23','2001-02-03'].forEach(function(d) {
  console.log(d + ': ' + eighteenThisYear(d));
});

使用 TypeScript 检查一个人今年是否达到特定年龄 (JavaScript)

Checking if a person is turning a specific age this year with TypeScript (JavaScript)

javascript

if-statement

date

unix-timestamp

typescript