mapbox-gl/js/ui/hash.js

A WebGL interactive maps library

'use strict';

/*
 * Adds the map's position to its page's location hash.
 * Passed as an option to the map object.
 *
 * @class mapboxgl.Hash
 * @returns {Hash} `this`
 */
module.exports = Hash;

var util = require('../util/util');
var window = require('../util/window');

function Hash() {
    util.bindAll([
        '_onHashChange',
        '_updateHash'
    ], this);
}

Hash.prototype = {
    /*
     * Map element to listen for coordinate changes
     *
     * @param {Object} map
     * @returns {Hash} `this`
     */
    addTo: function(map) {
        this._map = map;
        window.addEventListener('hashchange', this._onHashChange, false);
        this._map.on('moveend', this._updateHash);
        return this;
    },

    /*
     * Removes hash
     *
     * @returns {Popup} `this`
     */
    remove: function() {
        window.removeEventListener('hashchange', this._onHashChange, false);
        this._map.off('moveend', this._updateHash);
        delete this._map;
        return this;
    },

    _onHashChange: function() {
        var loc = window.location.hash.replace('#', '').split('/');
        if (loc.length >= 3) {
            this._map.jumpTo({
                center: [+loc[2], +loc[1]],
                zoom: +loc[0],
                bearing: +(loc[3] || 0),
                pitch: +(loc[4] || 0)
            });
            return true;
        }
        return false;
    },

    _updateHash: function() {
        var center = this._map.getCenter(),
            zoom = this._map.getZoom(),
            bearing = this._map.getBearing(),
            pitch = this._map.getPitch(),
            precision = Math.max(0, Math.ceil(Math.log(zoom) / Math.LN2)),

            hash = '#' + (Math.round(zoom * 100) / 100) +
                '/' + center.lat.toFixed(precision) +
                '/' + center.lng.toFixed(precision);

        if (bearing || pitch) hash += ('/' + (Math.round(bearing * 10) / 10));
        if (pitch) hash += ('/' + Math.round(pitch));

        window.history.replaceState('', '', hash);
    }
};