在 try-catch-finally 中使用 else-if 语句

Question

我正在尝试使用 try-catch-finally 语句来错误检查用户输入，如果没有错误则前进到下一页（我知道有更简单的方法可以做到这一点，但我需要使用try-catch-finally）。在这种情况下： foo 是用户的输入，输入需要是 0 到 100 之间的数字，displayDiagram() 会将用户前进到下一页。

在 finally 块之前，一切都对我有用。如果用户根本没有输入任何内容，它会前进到下一张幻灯片。如果什么都没有输入，如何阻止它前进？

代码如下：

 try {
      if (foo == "") throw "Enter your estimated score";
      if (isNaN(foo)) throw "Only use numbers for your estimated score";
      if (foo < 0) throw "Estimated score is not valid. Enter a higher number";
      if (foo > 100) throw "Estimated score is too high. Enter a lower number";

  }
  catch(err) {
    document.getElementById("fooMessage").innerHTML = err;
    document.getElementById("fooInput").style.borderColor = "red";

  }
  finally {
    if (err = undefined) {
     displayDiagram();
   }
 }

我尝试过的另一个 finally 块包括：

finally {
        if (preScore >= 0 && preScore <= 100) {
         displayDiagram();
       } else if (typeof preScore != "string") {
         displayDiagram();
        }
      }

有什么想法吗？谢谢！

Answer 1

你根本不需要 finally

try {
      if (foo == "") throw "Enter your estimated score";
      if (isNaN(foo)) throw "Only use numbers for your estimated score";
      if (foo < 0) throw "Estimated score is not valid. Enter a higher number";
      if (foo > 100) throw "Estimated score is too high. Enter a lower number";
      // any throw above will mean this doesn't get executed
      displayDiagram();

  }
  catch(err) {
    document.getElementById("fooMessage").innerHTML = err;
    document.getElementById("fooInput").style.borderColor = "red";

  }