govlab-styleguide
Version:
A styleguide / lightweight frontend framework for GovLab websites
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JavaScript
/**
* Magellan module.
* @module foundation.magellan
*/
!function(Foundation, $) {
'use strict';
/**
* Creates a new instance of Magellan.
* @class
* @fires Magellan#init
* @param {Object} element - jQuery object to add the trigger to.
* @param {Object} options - Overrides to the default plugin settings.
*/
function Magellan(element, options) {
this.$element = element;
this.options = $.extend({}, Magellan.defaults, this.$element.data(), options);
this._init();
Foundation.registerPlugin(this, 'Magellan');
}
/**
* Default settings for plugin
*/
Magellan.defaults = {
/**
* Amount of time, in ms, the animated scrolling should take between locations.
* @option
* @example 500
*/
animationDuration: 500,
/**
* Animation style to use when scrolling between locations.
* @option
* @example 'ease-in-out'
*/
animationEasing: 'linear',
/**
* Number of pixels to use as a marker for location changes.
* @option
* @example 50
*/
threshold: 50,
/**
* Class applied to the active locations link on the magellan container.
* @option
* @example 'active'
*/
activeClass: 'active',
/**
* Allows the script to manipulate the url of the current page, and if supported, alter the history.
* @option
* @example true
*/
deepLinking: false,
/**
* Number of pixels to offset the scroll of the page on item click if using a sticky nav bar.
* @option
* @example 25
*/
barOffset: 0
};
/**
* Initializes the Magellan plugin and calls functions to get equalizer functioning on load.
* @private
*/
Magellan.prototype._init = function() {
var id = this.$element[0].id || Foundation.GetYoDigits(6, 'magellan'),
_this = this;
this.$targets = $('[data-magellan-target]');
this.$links = this.$element.find('a');
this.$element.attr({
'data-resize': id,
'data-scroll': id,
'id': id
});
this.$active = $();
this.scrollPos = parseInt(window.pageYOffset, 10);
this._events();
};
/**
* Calculates an array of pixel values that are the demarcation lines between locations on the page.
* Can be invoked if new elements are added or the size of a location changes.
* @function
*/
Magellan.prototype.calcPoints = function(){
var _this = this,
body = document.body,
html = document.documentElement;
this.points = [];
this.winHeight = Math.round(Math.max(window.innerHeight, html.clientHeight));
this.docHeight = Math.round(Math.max(body.scrollHeight, body.offsetHeight, html.clientHeight, html.scrollHeight, html.offsetHeight));
this.$targets.each(function(){
var $tar = $(this),
pt = Math.round($tar.offset().top - _this.options.threshold);
$tar.targetPoint = pt;
_this.points.push(pt);
});
};
/**
* Initializes events for Magellan.
* @private
*/
Magellan.prototype._events = function() {
var _this = this,
$body = $('html, body'),
opts = {
duration: _this.options.animationDuration,
easing: _this.options.animationEasing
};
$(window).one('load', function(){
_this.calcPoints();
_this._updateActive();
});
this.$element.on({
'resizeme.zf.trigger': this.reflow.bind(this),
'scrollme.zf.trigger': this._updateActive.bind(this)
}).on('click.zf.magellan', 'a[href^="#"]', function(e) {
e.preventDefault();
var arrival = this.getAttribute('href'),
scrollPos = $(arrival).offset().top - _this.options.threshold / 2 - _this.options.barOffset;
// requestAnimationFrame is disabled for this plugin currently
// Foundation.Move(_this.options.animationDuration, $body, function(){
$body.stop(true).animate({
scrollTop: scrollPos
}, opts);
});
// });
};
/**
* Calls necessary functions to update Magellan upon DOM change
* @function
*/
Magellan.prototype.reflow = function(){
this.calcPoints();
this._updateActive();
};
/**
* Updates the visibility of an active location link, and updates the url hash for the page, if deepLinking enabled.
* @private
* @function
* @fires Magellan#update
*/
Magellan.prototype._updateActive = function(/*evt, elem, scrollPos*/){
var winPos = /*scrollPos ||*/ parseInt(window.pageYOffset, 10),
curIdx;
if(winPos + this.winHeight === this.docHeight){ curIdx = this.points.length - 1; }
else if(winPos < this.points[0]){ curIdx = 0; }
else{
var isDown = this.scrollPos < winPos,
_this = this,
curVisible = this.points.filter(function(p, i){
return isDown ? p <= winPos : p - _this.options.threshold <= winPos;//&& winPos >= _this.points[i -1] - _this.options.threshold;
});
curIdx = curVisible.length ? curVisible.length - 1 : 0;
}
this.$active.removeClass(this.options.activeClass);
this.$active = this.$links.eq(curIdx).addClass(this.options.activeClass);
if(this.options.deepLinking){
var hash = this.$active[0].getAttribute('href');
if(window.history.pushState){
window.history.pushState(null, null, hash);
}else{
window.location.hash = hash;
}
}
this.scrollPos = winPos;
/**
* Fires when magellan is finished updating to the new active element.
* @event Magellan#update
*/
this.$element.trigger('update.zf.magellan', [this.$active]);
};
/**
* Destroys an instance of Magellan and resets the url of the window.
* @function
*/
Magellan.prototype.destroy = function(){
this.$element.off('.zf.trigger .zf.magellan')
.find('.' + this.options.activeClass).removeClass(this.options.activeClass);
if(this.options.deepLinking){
var hash = this.$active[0].getAttribute('href');
window.location.hash.replace(hash, '');
}
Foundation.unregisterPlugin(this);
};
Foundation.plugin(Magellan, 'Magellan');
// Exports for AMD/Browserify
if (typeof module !== 'undefined' && typeof module.exports !== 'undefined')
module.exports = Magellan;
if (typeof define === 'function')
define(['foundation'], function() {
return Magellan;
});
}(Foundation, jQuery);