Confusion about how a promise returned by $ interval compares to $ timeout in Angular
I am having a problem understanding how a promise returned by a $ interval works in Angular.
Let's say in the following example, we have a simple "api" factory with a method called "getStuff" that returns an array with one element. We also have a controller that calls $ timeout on this factory:
angular.module("app",[])
.factory('api', function(){
return {
getStuff: function() {
return ["stuff"];
}
};
})
.controller('appCtrl', function($scope, $timeout, api){
$timeout(api.getStuff, 1000)
.then(function(response){
console.log(response);
});
})
This will write '["stuff"]' to the console after 1 second, which is great.
So let's say I want to call this method every time, replacing $ timeout with $ interval. Now nothing happens:
angular.module("app",[])
.factory('api', function(){
return {
getStuff: function() {
return ["stuff"];
}
};
})
.controller('appCtrl', function($scope, $interval, api){
$interval(api.getStuff, 1000)
.then(function(response){
console.log(response);
});
})
In this case, the difference between $ timeout and $ interval?
I appreciate all the help!
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The only thing you can do with a promise being returned $interval
is to cancel it (to stop it from being executed):
var handle = $interval(someFunc, 1000);
...
$interval.cancel(handle);
Your code should probably look like this:
app.controller('appCtrl', function($scope, $interval, api) {
$interval(function() {
console.log(api.getStuff());
}, 1000);
});
Be fantasy and see everything that works together:
app.controller('appCtrl', function($scope, $interval, $timeout, api) {
var handle = $interval(function() {
console.log(api.getStuff());
}, 1000);
$timeout(function() {
$interval.cancel(handle);
}, 5000);
});
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Added a counter value to the example provided by DIMM Reaper in a comment to Christophe L's answer:
/* APP MODULE */
var app = angular.module("app", []);
app.run(function ($interval) {
console.log('This fiddle will self destruct...');
var timer = $interval(function (count) {
console.log('tick... ' + count);
}, 500, 4, false);
timer.then(function(res) {
console.log("BOOM! " + res);
});
});
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.7.8/angular.min.js"></script>
<body ng-app="app">
</body>
Output:
This fiddle will self destruct...
tick... 1
tick... 2
tick... 3
tick... 4
BOOM! 4
The final result is the final result.
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