Javascript node.js+异步系列执行
在我的节点应用程序中,我使用async.series执行3个查询,它执行得非常好。。但在我的第三次查询执行中,我必须根据第三次查询的结果执行另一个查询,它也可以正常工作。但是我不能在第三个查询中执行一些逻辑,所以在所有查询完成之后,我只需要调用callback 我的代码:Javascript node.js+异步系列执行,javascript,node.js,asynchronous,Javascript,Node.js,Asynchronous,在我的节点应用程序中,我使用async.series执行3个查询,它执行得非常好。。但在我的第三次查询执行中,我必须根据第三次查询的结果执行另一个查询,它也可以正常工作。但是我不能在第三个查询中执行一些逻辑,所以在所有查询完成之后,我只需要调用callback 我的代码: async.series({ levels: function(cb) { sequelize.query("select country_id, country_name, level0, level
async.series({
levels: function(cb) {
sequelize.query("select country_id, country_name, level0, level1, level2, level3, level4 from levels").success(function(levelsResults) {
levelsResult = levelsResults;
cb(null, levelsResult);
})
},
level1: function(cb) {
sequelize.query("select id_0, name_0, name_1 from xxxxx group by id_0, name_0, name_1").success(function(level1Result) {
level1result = level1Result;
cb(null, level1result);
})
},
keys: function(cb) {
sequelize.query("select id_0 from xxxx group by id_0").success(function(id_0Result) {
var obj = {};
for (var i = 0; i < id_0Result.length; i++) {
sequelize.query("select id_0, value->>'yyyy' as value from xxxx where id_0 = " + id_0Result[i].id_0 + " limit 1").success(function(keyResult) {
var keyArray = [];
var keysObjectArray = [];
id_0 = keyResult[0].id_0;
keyResult = keyResult[0].value;
keyResult = JSON.parse(keyResult);
for (var prop in keyResult) {
keyArray.push(prop)
}
obj["" + id_0 + ""] = keyArray;
keysObjectArray.push(obj);
cb(null, keysObjectArray);
---.my problem is here cb is called in the 1st iteration of
for loop.It should be called after loop finishes
})
}
})
}
}, function seriesFinal(seriesErr, seriesResults) {
if (seriesErr) throw new Error("Something bad!");
onSuccess(JSON.stringify(seriesResults), callback);
});
但我期待的是:
{"levels":[{levsls}],"level1":[{level1}],"keys":[{},{}]};
编辑:
简单地说,我如何使sequalize查询执行for循环并最终调用回调
请帮助我解决此问题。。提前感谢。…for循环运行n个查询,随机回调success函数 您可以使用计数器确保所有查询都被回调
sequelize.query("select id_0 from xxxx group by id_0").success(function(id_0Result){
var obj = {};
var counter = 0;
for(var i=0; i<id_0Result.length; i++){
sequelize.query("select id_0, value->>'yyyy' as value from xxxx where id_0 = "+id_0Result[i].id_0+" limit 1").success(function(keyResult){
var keyArray=[];
var keysObjectArray =[];
id_0 = keyResult[0].id_0;
keyResult = keyResult[0].value;
keyResult = JSON.parse(keyResult);
for (var prop in keyResult){
keyArray.push(prop)
}
obj[""+id_0+""] = keyArray;
keysObjectArray.push(obj);
counter +=1;
if(counter === id_0Result.length )
{
cb(null, keysObjectArray);
}
})
}
请注意,KeyObjectArray中的顺序是随机的,回调也是随机的
希望能有帮助
Yoann不仅仅是async.series!您可以使用async.forEach执行循环,对于键函数,async.map将很好地执行以下操作:
keys: function(cb) {
sequelize.query("select id_0 from xxxx group by id_0").success(function(id_0Result){
var obj = {};
// Loop over each object in id_0Result,
// and transform it into a new array
async.map(
id_0Result,
function(result, cb) {
sequelize.query("select id_0, value->>'yyyy' as value from xxxx where id_0 = "+result.id_0+" limit 1").success(function(keyResult){
var keyArray=[];
id_0 = keyResult[0].id_0;
keyResult = keyResult[0].value;
keyResult = JSON.parse(keyResult);
for (var prop in keyResult){
keyArray.push(prop)
}
obj[""+id_0+""] = keyArray;
// Add this object to the array result for async.map
return cb(null, obj);
})
},
// Call the callback for async.series with the result of
// the mapping; effectively cb(null, transformedArray)
cb
);
});
}
谢谢@Scott Gress..我还有一个疑问。。我有一个对象数组。如果可以通过从我的对象中获取id_0来创建键值对,我想async.map会对我有所帮助。。
keys: function(cb) {
sequelize.query("select id_0 from xxxx group by id_0").success(function(id_0Result){
var obj = {};
// Loop over each object in id_0Result,
// and transform it into a new array
async.map(
id_0Result,
function(result, cb) {
sequelize.query("select id_0, value->>'yyyy' as value from xxxx where id_0 = "+result.id_0+" limit 1").success(function(keyResult){
var keyArray=[];
id_0 = keyResult[0].id_0;
keyResult = keyResult[0].value;
keyResult = JSON.parse(keyResult);
for (var prop in keyResult){
keyArray.push(prop)
}
obj[""+id_0+""] = keyArray;
// Add this object to the array result for async.map
return cb(null, obj);
})
},
// Call the callback for async.series with the result of
// the mapping; effectively cb(null, transformedArray)
cb
);
});
}