我收到有关未从 Bluebird 返回已创建 promise 的警告,但我不明白为什么以及如何重写我的代码。
(我已尝试阅读 Bluebird API 页面和 anti-pattern page 上的警告,因为我怀疑这是我正在做的)
在我的 view.js 文件中:
var express = require('express'),
router = express.Router(),
settings = myReq('config/settings'),
Sets = myReq('lib/Sets'),
log = myReq('lib/utils').getLogger('View');
router.get('/:setId/', function(req, res, next) {
var
setId = req.params.setId,
user = req.user,
set = new Sets(setId, user);
log.info('Got a request for set: ' + setId);
// The below line gives the warning mentioned
set.getSet().then(function(output) {
res.send(output);
}).error(function(e){
log.error(e.message, e.data);
res.send('An error occurred while handling set:' + e.message);
});
});
module.exports = router;
在我的 Sets.js 文件中,我有:
var
Promise = require('bluebird'),
OE = Promise.OperationalError,
settings = myReq('config/settings'),
UserData = myReq('lib/userData'),
log = myReq('lib/utils').getLogger('sets'),
errorToSend = false;
module.exports = function(setId, user) {
var
sets = myReq('lib/utils').getDb('sets');
return {
getSet : function() {
log.debug('Getting set')
return sets.findOneAsync({
setId:setId
}).then(function(set){
if ( set ) {
log.debug('got set from DB');
} else {
set = getStaticSet(setId);
if ( ! set ) {
throw new OE('Failed getting db records or static template for set: ' + setId );
}
log.debug('got static set');
}
log.debug('I am handling set')
if ( ! checkSet(set) ) {
var e = new OE('Failed checking set');
e.data = set;
throw e;
}
return {
view : getView(set),
logic : set.logic,
canEdit : true,
error : errorToSend
};
});
}
};
};
所以我的 view.js 文件中带有“set.getSet()”的行给出了关于不返回创建的 promise 的警告。该脚本似乎仍然按照我的预期执行,但我不明白为什么会收到警告。
堆栈跟踪:
Warning: a promise was created in a handler but was not returned from it
at Object.getSet (C:\dev\infoscrn\lib\Sets.js:36:25)
at C:\dev\infoscrn\routes\view.js:39:20
at Layer.handle [as handle_request] (C:\dev\infoscrn\node_modules\express\lib\router\layer.js:82:5)
at next (C:\dev\infoscrn\node_modules\express\lib\router\route.js:110:13)
at Route.dispatch (C:\dev\infoscrn\node_modules\express\lib\router\route.js:91:3)
at Layer.handle [as handle_request] (C:\dev\infoscrn\node_modules\express\lib\router\layer.js:82:5)
at C:\dev\infoscrn\node_modules\express\lib\router\index.js:267:22
at param (C:\dev\infoscrn\node_modules\express\lib\router\index.js:340:14)
at param (C:\dev\infoscrn\node_modules\express\lib\router\index.js:356:14)
at Function.proto.process_params (C:\dev\infoscrn\node_modules\express\lib\router\index.js:400:3)
at next (C:\dev\infoscrn\node_modules\express\lib\router\index.js:261:10)
at Function.proto.handle (C:\dev\infoscrn\node_modules\express\lib\router\index.js:166:3)
at router (C:\dev\infoscrn\node_modules\express\lib\router\index.js:35:12)
at Layer.handle [as handle_request] (C:\dev\infoscrn\node_modules\express\lib\router\layer.js:82:5)
at trim_prefix (C:\dev\infoscrn\node_modules\express\lib\router\index.js:302:13)
at C:\dev\infoscrn\node_modules\express\lib\router\index.js:270:7
at Function.proto.process_params (C:\dev\infoscrn\node_modules\express\lib\router\index.js:321:12)
at next (C:\dev\infoscrn\node_modules\express\lib\router\index.js:261:10)
at C:\dev\infoscrn\node_modules\express\lib\router\index.js:603:15
at next (C:\dev\infoscrn\node_modules\express\lib\router\index.js:246:14)
最佳答案
首先,尝试 update all your dependencies .有一个最新版本的 Bluebird,它修复了 an issue involving this warning .
接下来,请确保您是 return from all your handlers .
然后,如果您仍然收到警告(像我一样),您可以 disable this specific warning .我选择通过在我的环境中设置 BLUEBIRD_W_FORGOTTEN_RETURN=0
来做到这一点。
关于node.js - Bluebird 警告 "A promise was created in a handler but was not returned from it",我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/34370957/