javascript - 数字加一个数字在Javascript中是NaN

Question

我很生气这是多么愚蠢。这怎么可能？

  console.log(typeof form.timeCompletedInSeconds);
  console.log(typeof totalTimeCompletion);

  console.log(totalTimeCompletion);
  console.log(form.timeCompletedInSeconds);

  totalTimeCompletion = form.timeCompletedInSecond + totalTimeCompletion;
  console.log(totalTimeCompletion)

输出：

number
number
0
3
NaN

标签： javascript

Answer 1

你需要写timeCompletedInSeconds而不是timeCompletedInSecond在第 6 行。你在最后错过了s，这就是你得到undefined + 3 = NaN.