Can I delay the keyup event for jquery?

Paul picture Paul · Apr 1, 2012 · Viewed 12.4k times · Source

I'm using the rottentomatoes movie API in conjunction with twitter's typeahead plugin using bootstrap 2.0. I've been able to integerate the API but the issue I'm having is that after every keyup event the API gets called. This is all fine and dandy but I would rather make the call after a small pause allowing the user to type in several characters first.

Here is my current code that calls the API after a keyup event:

    var autocomplete = $('#searchinput').typeahead()
    .on('keyup', function(ev){

        ev.stopPropagation();
        ev.preventDefault();

        //filter out up/down, tab, enter, and escape keys
        if( $.inArray(ev.keyCode,[40,38,9,13,27]) === -1 ){

            var self = $(this);

            //set typeahead source to empty
            self.data('typeahead').source = [];

            //active used so we aren't triggering duplicate keyup events
            if( !self.data('active') && self.val().length > 0){

                self.data('active', true);

                //Do data request. Insert your own API logic here.
                $.getJSON("http://api.rottentomatoes.com/api/public/v1.0/movies.json?callback=?&apikey=MY_API_KEY&page_limit=5",{
                    q: encodeURI($(this).val())
                }, function(data) {

                    //set this to true when your callback executes
                    self.data('active',true);

                    //Filter out your own parameters. Populate them into an array, since this is what typeahead's source requires
                    var arr = [],
                        i=0;

                    var movies = data.movies;

                     $.each(movies, function(index, movie) {
                        arr[i] = movie.title
                        i++;
                     });

                    //set your results into the typehead's source 
                    self.data('typeahead').source = arr;

                    //trigger keyup on the typeahead to make it search
                    self.trigger('keyup');

                    //All done, set to false to prepare for the next remote query.
                    self.data('active', false);

                });

            }
        }
    });

Is it possible to set a small delay and avoid calling the API after every keyup?

Answer

Vitaly  Muminov picture Vitaly Muminov · Apr 1, 2012

it can be easily done like this:

var autocomplete = $('#searchinput').typeahead().on('keyup', delayRequest);

function dataRequest() {
    // api request here
}

function delayRequest(ev) {
    if(delayRequest.timeout) {
        clearTimeout(delayRequest.timeout);
    }

    var target = this;

    delayRequest.timeout = setTimeout(function() {
        dataRequest.call(target, ev);
    }, 200); // 200ms delay
}