The try...catch..finally statement specifies a block of code to try along with a response should an error occur. The try statement contains one or more try blocks, and ends with at least one catch and/or a finally clause.

try...catch..finally语句指定代码块，以在发生错误时尝试与响应一起使用。 try语句包含一个或多个try块，并以至少一个catch和/或finally子句结尾。

try...catch ： (try...catch:)

try {throw new Error('my error');
} catch (err) {console.error(err.message);
}// Output: my error

try...finally ： (try...finally:)

try {throw new Error('my error');
} finally {console.error('finally');
}// Output: finally

When you don't use a catch statement, the error is not "caught", even though the code in the finally block is executed. Instead, the error will continue to the upper try block (or main block).

当您不使用catch语句时，即使执行了finally块中的代码，也不会“捕获”该错误。 而是，错误将继续到上部try块(或主块)。

try...catch...finally ： (try...catch...finally:)

try {throw new Error('my error');
} catch (err) {console.error(err.message);
} finally {console.error('finally');
}// Output:
// my error
// finally

Typical usage:

典型用法：

try {openFile(file);readFile(file)
} catch (err) {console.error(err.message);
} finally {closeFile(file);
}

嵌套try...catch ： (Nested try...catch:)

You can also:

你也可以：

• Nest a try-catch statement inside a try block.

  将try-catch语句嵌套在try块内。

You can nest a try...catch statement within a try block. For example, to throw an error upwards:

您可以在try块中嵌套try...catch语句。 例如，向上抛出错误：

try {try {throw new Error('my error');} catch (err) {console.error('inner', err.message);throw err;} finally {console.log('inner finally');}
} catch (err) {console.error('outer', err.message);
}// Output:
// inner my error
// inner finally
// outer my error

翻译自: https://www.freecodecamp.org/news/error-handling-and-try-catch-throw/