Javascript尝试... catch ... else ...最后像Python，Java，Ruby等 [英] Javascript try...catch...else...finally like Python, Java, Ruby, etc

问题描述

Javascript如何复制四部分尝试 - catch - else - 最后其他语言支持的执行模型？

一个清晰的简短摘要来自 Python 2.5新功能。在Javascript术语中：

  // XXX此示例是语法错误
尝试{
 //受保护-block 
} catch（e）{
 // Handler-block 
} else {
 // Else-block 
} finally {
 //最终区块
} 
  

受保护区块中的代码被执行。如果代码抛出异常，则执行 Handler-block ;如果没有抛出异常，则执行 Else-block 。

无论以前发生了什么， Final-block 在代码块完成并处理任何抛出的异常后执行。即使处理程序块或 Else-block 出现错误并引发新的异常， Final-block 中的代码仍会运行。

请注意，在受保护区块结尾处剪切 Else-block 并粘贴错误。如果 Else-block 中发生错误，则处理程序块 class =h2_lin>解决方案

将jhs的概念扩展一点，整个概念可以放在一个函数中，以提供更多的可读性：

  var try_catch_else_finally = function（protected_code，handler_code，else_code，finally_code）{
 try {
 var success = true; 
 try {
 protected_code（）; 
} catch（e）{
 success = false; 
 handler_code（{exception_was：e}）; 
} 
 if（success）{
 else_code（）; 
} 
} finally {
 finally_code（）; 
} 
}; 
  

然后我们可以像这样使用它（非常类似于python方式）：

  try_catch_else_finally（function（）{
 // protected block 
}，function（）{
 // handler block 
}，function（）{
 // else block 
}，function（）{
 // final-block 
}）; 
  

How can Javascript duplicate the four-part try-catch-else-finally execution model that other languages support?

A clear, brief summary is from the Python 2.5 what's new. In Javascript terms:

// XXX THIS EXAMPLE IS A SYNTAX ERROR
try {
  // Protected-block
} catch(e) {
  // Handler-block
} else {
  // Else-block
} finally {
  // Final-block
}

The code in Protected-block is executed. If the code throws an exception, Handler-block is executed; If no exception is thrown, Else-block is executed.

No matter what happened previously, Final-block is executed once the code block is complete and any thrown exceptions handled. Even if there’s an error in Handler-block or Else-block and a new exception is raised, the code in Final-block is still run.

Note that cutting Else-block and pasting at the end of Protected-block is wrong. If an error happens in Else-block, it must not be handled by Handler-block.

解决方案

Extending the idea of jhs a little, the whole concept could be put inside a function, to provide even more readability:

var try_catch_else_finally = function(protected_code, handler_code, else_code, finally_code) {
  try {
    var success = true;
    try {
      protected_code();
    } catch(e) {
      success = false;
      handler_code({"exception_was": e});
    }
    if(success) {
      else_code();
    }
  } finally {
    finally_code();
  }
};

Then we can use it like this (very similar to the python way):

try_catch_else_finally(function() {
  // protected block
}, function() {
  // handler block
}, function() {
  // else block
}, function() {
  // final-block
});

这篇关于Javascript尝试... catch ... else ...最后像Python，Java，Ruby等的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！