Try catch exception capture mechanism usage analysis _javascript techniques in JavaScript

The examples in this article describe the use of Try catch exception capture mechanisms in JavaScript. Share to everyone for your reference, specific as follows:

1. Like Java, JavaScript also has a try catch block, which is the mechanism for exception capture.

(1) A typical try Catch statement

try{
}
catch{
}
finally{
}

As in Java, the most typical try catch statement in JS is also divided into three parts, and try is used to catch exceptions, catch to handle exceptions, and finally to close resources for subsequent operations.

Example:

try{
  Throw "error"
}
catch (ex)
{
  console.log (ex);
}
finally{
  Console.log ("finally")
}

Console output in turn: error,finally

(2) in try,catch blocks, catch blocks and finally blocks only need one, so the following try catch blocks are also possible

Example:

try {
  throw "error"
}
finally{
}

Throw exception only, other case is not an example

(3) A try catch block is included in a try Catch block

try{ 
   try{
       Throw "error"
     }
   finally{
      console.log ("Finally1")
     }
\
catch (ex)
{
   Console.log (ex)
}
finally{
  console.log ("Finally2")
}

In the case of nested loops like this, the order of output is: finally1,error,finally2

(4) Nested try catch blocks, throwing exceptions

try{
   try{
      throw "Error1"
   }
   catch (ex)
   { 
      console.log (ex);
      Throw "Error2"
   }
   finally{
     console.log ("Finally1")
   }
catch (ex)
{
    Console.log (ex);
}
finally{
   console.log ("Finally2")
}

The final output is: error1,finally1,error2,finally2

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I hope this article will help you with JavaScript programming.