ank5
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Node js - send response after all promises are resolved
I have a route defined in NodeJS Express.
The route calls a function multiple times (which returns a promise). Value returned from these Promises are added to an Array which is then send back to the client using res.json().
The problem that I am facing is that while Promises are getting resolved, res.json() executes as it does not wait for the Promises to return. I think some kind of chaining mechanism would be needed but can't make out how to do it.
Below is my code
How can I ensure that ' res.json(markers);' is executed after all the three Promises are resolved.
The route calls a function multiple times (which returns a promise). Value returned from these Promises are added to an Array which is then send back to the client using res.json().
The problem that I am facing is that while Promises are getting resolved, res.json() executes as it does not wait for the Promises to return. I think some kind of chaining mechanism would be needed but can't make out how to do it.
Below is my code
app.get('/markers', function(req, res) {
var markers = [];
var marker1 = {"id": 1, "name": "London"};
// Get the lat and lng based on the address
geocoding(marker1.name).then(function(geocode) {
marker1.lat = geocode[0].latitude;
marker1.lng = geocode[0].longitude;
markers.push(marker1);
}, function(error) {
console.log(error);
})
var marker2 = {"id": 2, "name": "Chicago" };
geocoding(marker2.name).then(function(geocode) {
marker2.lat = geocode[0].latitude;
marker2.lng = geocode[0].longitude;
markers.push(marker2);
}, function(error) {
console.log(error);
})
var marker3 = {"id": 3, "name": "Munich" };
geocoding(marker3.name).then(function(geocode) {
marker3.lat = geocode[0].latitude;
marker3.lng = geocode[0].longitude;
markers.push(marker3);
}, function(error) {
console.log(error);
})
// return the lat and lng array to the client
res.json(markers);
})
How can I ensure that ' res.json(markers);' is executed after all the three Promises are resolved.
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