如何停止执行 node.js 脚本？
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How to stop execution of a node.js script?
提问by AJB
Say I've got this script:
说我有这个脚本：
var thisIsTrue = false;
exports.test = function(request,response){
if(thisIsTrue){
response.send('All is good!');
}else{
response.send('ERROR! ERROR!');
// Stop script execution here.
}
console.log('I do not want this to happen if there is an error.');
}
And as you can see, I'd like to stop the script from executing any downstream functions if there's an error.
如您所见，如果出现错误，我想阻止脚本执行任何下游函数。
I've managed to achieve this by adding return;after the error response is sent:
我设法通过return;在发送错误响应后添加来实现这一点：
var thisIsTrue = false;
exports.test = function(request,response){
if(thisIsTrue){
response.send('All is good!');
}else{
response.send('ERROR! ERROR!');
return;
}
console.log('I do not want this to happen if there is an error.');
}
But is that the 'correct' way to do things?
但这是做事的“正确”方式吗？
Alternatives
备择方案
I've also seen examples that use process.exit();and process.exit(1);, but that gives me a 502 Bad Gatewayerror (I assume because it kills node?).
我也看过使用process.exit();and 的例子process.exit(1);，但这给了我一个502 Bad Gateway错误（我假设是因为它杀死了节点？）。
And callback();, which just gave me an 'undefined' error.
而且callback();，这只是给了我一个“未定义”的错误。
What is the 'correct' way to stop a node.js script at any given point and prevent any downstream functions from executing?
在任何给定点停止 node.js 脚本并阻止任何下游函数执行的“正确”方法是什么？
回答by Tim Brown
Using a returnis the correct way to stop a function executing. You are correct in that process.exit()would kill the whole node process, rather than just stopping that individual function. Even if you are using a callback function, you'd want to return it to stop the function execution.
使用 areturn是停止函数执行的正确方法。您是正确的，这process.exit()会杀死整个节点进程，而不仅仅是停止该单个功能。即使您正在使用回调函数，您也希望返回它以停止函数执行。
ASIDE: The standard callback is a function where the first argument is an error, or null if there was no error, so if you were using a callback the above would look like:
旁白：标准回调是一个函数，其中第一个参数是错误，如果没有错误，则为 null，因此如果您使用的是回调，则上述内容如下所示：
var thisIsTrue = false;
exports.test = function(request, response, cb){
if (thisIsTrue) {
response.send('All is good!');
cb(null, response)
} else {
response.send('ERROR! ERROR!');
return cb("THIS ISN'T TRUE!");
}
console.log('I do not want this to happen. If there is an error.');
}
回答by mate.gwozdz
You should use return, which will help you respond to what happened. Here's a bit cleaner version, basically first validate whatever you want to validate, rather than encapsulating everything in if{}else{} statements
您应该使用return，这将帮助您对发生的事情做出反应。这是一个更简洁的版本，基本上首先验证您要验证的任何内容，而不是将所有内容封装在 if{}else{} 语句中
exports.test = function(request, response, cb){
if (!thisIsTrue) {
response.send('ERROR! ERROR!');
return cb("THIS ISN'T TRUE!");
}
response.send('All is good!');
cb(null, response)
console.log('I do not want this to happen. If there is an error.');
}
Another way would be to use throw
另一种方法是使用 throw
exports.test = function(request, response, cb){
if (!thisIsTrue) {
response.send('ERROR! ERROR!');
cb("THIS ISN'T TRUE!");
throw 'This isn\'t true, perhaps it should';
}
response.send('All is good!');
cb(null, response)
console.log('I do not want this to happen. If there is an error.');
}
Finally, examples that would stop entire app from further execution:
最后，会阻止整个应用程序进一步执行的示例：
a) Throw an error, which will also help you debug the app (wouldn't completely stop the app, if the test()function was wrapper in try{}catch(e){}):
a) 抛出一个错误，这也将帮助您调试应用程序（不会完全停止应用程序，如果test()函数在 中包装try{}catch(e){}）：
throw new Error('Something went wrong')
throw new Error('Something went wrong')
b) Stop script execution (works with Node.js):
b) 停止脚本执行（适用于 Node.js）：
process.exit()
process.exit()
