Designing a fluid Javascript interface to hide callback asynchrony
- by Anurag
How would I design an API to hide the asynchronous nature of AJAX and HTTP requests, or basically delay it to provide a fluid interface. To show an example from Twitter's new Anywhere API:
// get @ded's first 20 statuses, filter only the tweets that
// mention photography, and render each into an HTML element
T.User.find('ded').timeline().first(20).filter(filterer).each(function(status) {
$('div#tweets').append('<p>' + status.text + '</p>');
});
function filterer(status) {
return status.text.match(/photography/);
}
vs this (asynchronous nature of each call is clearly visible)
T.User.find('ded', function(user) {
user.timeline(function(statuses) {
statuses.first(20).filter(filterer).each(function(status) {
$('div#tweets').append('<p>' + status.text + '</p>');
});
});
});
It finds the user, gets their tweet timeline, filters only the first 20 tweets, applies a custom filter, and ultimately uses the callback function to process each tweet.
I am guessing that a well designed API like this should work like a query builder (think ORMs) where each function call builds the query (HTTP URL in this case), until it hits a looping function such as each/map/etc., the HTTP call is made and the passed in function becomes the callback.
An easy development route would be to make each AJAX call synchronous, but that's probably not the best solution. I am interested in figuring out a way to make it asynchronous, and still hide the asynchronous nature of AJAX.
