I've attempted multiple methods, but still haven't found a solution to this issue.
Within my code, there is a method called iterator that returns a promise; this method runs in a loop x number of times. If the iterator function returns a rejected promise, I want the execution to stop and proceed to the error block.
I tried implementing the solution from this SO answer, but it continues executing for all iterations despite encountering an error.
var foo = function(formdata) {
var d = $q.defer();
CallService.init()
.then(function(response) {
return CallService.fun1(formdata);
})
.then(function(response) {
var row = {1:'one', 2:'two', 3: 'three' };
var promiseArray = [];
if (<key condition true>) {
var promise = Object.keys(row).map(function(i) {
return iterator(i, row[i]).then(function(response){
promiseArray.push(response);
}, function(err){
return $q.reject(err);
});
});
return $q.all(promise); // reject if anyone is rejected, otherwise resolve
}
else {
d.reject({
message: "key condition failed."
});
}
return d.promise;
})
.then(successHandler)
.catch(errorHandler);
};
The iterator function being called in each iteration is defined as:
var iterator = function(num, data) {
var d = $q.defer();
CallService.fun3()
.then(function(response) {
return CallService.fun4(data)
})
.then(function(response) {
d.resolve(num);
})
.catch(function(err) {
d.reject(err);
});
return d.promise;
};
The goal is to stop the loop if iterator sends a rejection on the first call, but all iterations are currently running even after an error is encountered.
I have also attempted the following approach:
var d = $q.defer();
for (var k in row) {
if (isCalled) break;
var promise = iterator(k, row[k]);
promise.then(function(response) {
promiseArray.push(response);
}, function(err) {
isCalled = true;
d.reject(err);
});
}
if (!isCalled && promiseArray.length > 0) {
console.log('after for loop', promiseArray);
d.resolve(promiseArray);
}
return d.promise;
Despite trying different methods, the loop executes for all iterations regardless of any rejected promises.
Edit
I explored using the .reduce method, which partially worked. However, I need to include the promiseArray along with the error when a rejection occurs. Here is the revised code snippet:
var first_promise = $q.resolve();
var start_promise = Object.keys(row).reduce(function(promise, key){
return promise.then(function(result){
if(angular.isDefined(result))
promiseArray.push(result);
return iterator(key, row[key]);
});
}, first_promise);
start_promise.then(function(res){
return $q.when(promiseArray);
}).catch(function(err){
return $q.reject();
});