terriajs/lib/Core/pollToPromise.js

Geospatial data visualization platform.

'use strict';

/*global require*/
var defaultValue = require('terriajs-cesium/Source/Core/defaultValue');
var getTimestamp = require('terriajs-cesium/Source/Core/getTimestamp');
var when = require('terriajs-cesium/Source/ThirdParty/when');

var pollToPromise = function(f, options) {
    options = defaultValue(options, defaultValue.EMPTY_OBJECT);

    var pollInterval = defaultValue(options.pollInterval, 1);
    var timeout = defaultValue(options.timeout, 5000);

    var deferred = when.defer();

    var startTimestamp = getTimestamp();
    var endTimestamp = startTimestamp + timeout;

    function poller() {
        if (f()) {
            deferred.resolve();
        } else {
            if (getTimestamp() > endTimestamp) {
                deferred.reject();
            } else {
                setTimeout(poller, pollInterval);
            }
        }
    }

    poller();

    return deferred.promise;
};

module.exports = pollToPromise;