我正在使用 co
运行一个生成器函数,该函数对数据进行一些抓取和清理。但是,我在循环后从未到达代码的特定部分。我的代码如下所示:
function*(){
var url = "mongodb://" + config.host + ":" + config.port + "/" + config.db;
var db = yield MongoClient.connect( url );
for( var establishment in [ {"establishment_id": 16} ] ){
var establishment_type = establishment.id;
var response = yield getRestaurants( establishment_type );
var restaurants = JSON.parse( response.body ).restaurants;
// here we create our restaurants in "saveable" form
var saveableRestaurants = [];
for(var i = 0; i < restaurants.length; i++){
var saveableRestaurant = restaurants[i].restaurant;
saveableRestaurant._id = restaurants[i].restaurant.R.res_id;
// Remove unwanted fields
//... code removed for brevity ...
// convert cuisine string into its appropriate id form
var cuisines = saveableRestaurant.cuisines.split(",");
var ids = [];
for( var i = 0; i < cuisines.length; i++ ){
console.log("LOOKING UP ID FOR ", cuisines[i]);
var match = yield db.collection(CUI).findOne({"cuisine_name":cuisines[i].trim()});
console.log("ID FOR ", cuisines[i], " IS", match.cuisine_id);
ids.push( id );
}
// I NEVER REACH THIS LINE!!!!
console.log( "ALL IDS ", ids );
}
}
db.close();
}
我从来没有到达函数末尾的控制台语句
最佳答案
很可能存在您没有注意到的异步异常。你应该使用
function*() {
var url = "mongodb://" + config.host + ":" + config.port + "/" + config.db;
var db = yield MongoClient.connect( url );
try {
for (var establishment of [ {"establishment_id": 16} ]) {
var establishment_type = establishment.id;
var response = yield getRestaurants( establishment_type );
var restaurants = JSON.parse( response.body ).restaurants;
// here we create our restaurants in "saveable" form
var saveableRestaurants = [];
for (var i = 0; i < restaurants.length; i++) {
var saveableRestaurant = restaurants[i].restaurant;
saveableRestaurant._id = restaurants[i].restaurant.R.res_id;
// Remove unwanted fields
//... code removed for brevity ...
// convert cuisine string into its appropriate id form
var cuisines = saveableRestaurant.cuisines.split(",");
var ids = [];
for (var i = 0; i < cuisines.length; i++) {
console.log("LOOKING UP ID FOR ", cuisines[i]);
var match = yield db.collection(CUI).findOne({"cuisine_name":cuisines[i].trim()});
console.log("ID FOR ", cuisines[i], " IS", match.cuisine_id);
ids.push( id );
}
console.log( "ALL IDS ", ids );
}
}
} finally {
db.close();
}
}
另外,不要忘记在 co
返回的 Promise 上添加 .catch(e => console.error(e))
。
关于javascript - NodeJS 生成器永远不会到达某一行?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/35846839/