I'm having trouble understanding how to adapt single Promises to a chain of Promises that resolves once both API calls have returned.
How would one rewrite the code below to be a chain of Promises?
function parseTweet(tweet) { indico.sentimentHQ(tweet) .then(function(res) { tweetObj.sentiment = res; }).catch(function(err) { console.warn(err); }); indico.organizations(tweet) .then(function(res) { tweetObj.organization = res[0].text; tweetObj.confidence = res[0].confidence; }).catch(function(err) { console.warn(err); }); }
Thanks.
If you want the calls to run concurrently then you can use Promise.all .
Promise.all([indico.sentimentHQ(tweet), indico.organizations(tweet)])
.then(values => {
// handle responses here, will be called when both calls are successful
// values will be an array of responses [sentimentHQResponse, organizationsResponse]
})
.catch(err => {
// if either of the calls reject the catch will be triggered
});
You can also chain them by returning them as a chain but it is not as efficient as the promise.all() - approach (This is just do this, then that, then something else etc) If you need the result of api-call 1 for api-call 2 this would be the way to go:
function parseTweet(tweet) {
indico.sentimentHQ(tweet).then(function(res) {
tweetObj.sentiment = res;
//maybe even catch this first promise error and continue anyway
/*}).catch(function(err){
console.warn(err);
console.info('returning after error anyway');
return true; //continues the promise chain after catching the error
}).then(function(){
*/
return indico.organizations(tweet);
}).then(function(res){
tweetObj.organization = res[0].text;
tweetObj.confidence = res[0].confidence;
}).catch(function(err) {
console.warn(err);
});
}
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