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本文介绍了Javascript尝试... catch ... else ...最后像Python，Java，Ruby等的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
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。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
});
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