autoscroll/lib/autoScroll.js

A utility for auto-scroll when almost reach boundary

'use strict';

Object.defineProperty(exports, "__esModule", {
    value: true
});

var _lodash = require('lodash.throttle');

var _lodash2 = _interopRequireDefault(_lodash);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

var setup = function setup() {
    var autoScrollCtrl = {};

    var stopAutoScrolling = function stopAutoScrolling() {
        var cancelAnimationFrame = window.cancelAnimationFrame || window.mozCancelAnimationFrame;
        cancelAnimationFrame(autoScrollCtrl.pid);
    };

    var _autoScroll = function _autoScroll( /**Event*/evt, /**Object*/options, /**HTMLElement*/rootEl) {
        var scrollParentEl = void 0;
        var scrollEl = void 0;

        // Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=505521
        if (rootEl && options.scroll) {
            var el = void 0;
            var rect = void 0;
            var sens = options.scrollSensitivity;
            var speed = options.scrollSpeed;
            var x = evt.clientX;
            var y = evt.clientY;
            var winWidth = window.innerWidth;
            var winHeight = window.innerHeight;
            var vx = void 0,
                vy = void 0,
                scrollOffsetX = void 0,
                scrollOffsetY = void 0;

            // Delect scrollEl
            if (scrollParentEl !== rootEl) {
                scrollEl = options.scroll;
                scrollParentEl = rootEl;

                if (scrollEl === true) {
                    scrollEl = rootEl;

                    do {
                        if (scrollEl.offsetWidth < scrollEl.scrollWidth) {
                            break;
                        }

                        if (scrollEl.offsetHeight < scrollEl.scrollHeight) {
                            break;
                        }

                        if (!scrollEl.parentNode) {
                            break;
                        }

                        scrollEl = scrollEl.parentNode;
                    } while (true);
                }
            }

            if (scrollEl) {
                el = scrollEl;
                rect = scrollEl.getBoundingClientRect();
                vx = (Math.abs(rect.right - x) <= sens) - (Math.abs(rect.left - x) <= sens);
                vy = (Math.abs(rect.bottom - y) <= sens) - (Math.abs(rect.top - y) <= sens);
            }

            if (!(vx || vy)) {
                vx = (winWidth - x <= sens) - (x <= sens);
                vy = (winHeight - y <= sens) - (y <= sens);

                if (vx || vy) {
                    el = window;
                }
            }

            if (autoScrollCtrl.vx !== vx || autoScrollCtrl.vy !== vy || autoScrollCtrl.el !== el) {
                autoScrollCtrl.el = el;
                autoScrollCtrl.vx = vx;
                autoScrollCtrl.vy = vy;

                stopAutoScrolling(); // Stop any exist autoScrolling
                if (el) {
                    var requestAnimationFrame = window.requestAnimationFrame || window.mozRequestAnimationFrame || window.webkitRequestAnimationFrame || window.msRequestAnimationFrame;
                    var scrolling = function scrolling() {
                        scrollOffsetY = vy ? vy * speed : 0;
                        scrollOffsetX = vx ? vx * speed : 0;

                        if (el === window) {
                            window.scrollTo(window.pageXOffset + scrollOffsetX, window.pageYOffset + scrollOffsetY);
                        } else {
                            el.scrollTop += scrollOffsetY;
                            el.scrollLeft += scrollOffsetX;
                        }

                        autoScrollCtrl.pid = requestAnimationFrame(scrolling);
                    };
                    autoScrollCtrl.pid = requestAnimationFrame(scrolling);
                }
            }
        }
    };

    var throttleAutoScroll = (0, _lodash2.default)(_autoScroll, 30);
    var run = function run( /**Event*/evt, /**HTMLElement*/rootEl) {
        var options = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : {};
        var _options$scroll = options.scroll,
            scroll = _options$scroll === undefined ? true : _options$scroll,
            _options$scrollSensit = options.scrollSensitivity,
            scrollSensitivity = _options$scrollSensit === undefined ? 30 : _options$scrollSensit,
            _options$scrollSpeed = options.scrollSpeed,
            scrollSpeed = _options$scrollSpeed === undefined ? 10 : _options$scrollSpeed;

        var newOptions = {
            scroll: scroll,
            scrollSensitivity: scrollSensitivity,
            scrollSpeed: scrollSpeed
        };

        throttleAutoScroll(evt, newOptions, rootEl);
    };

    return {
        run: run,
        end: stopAutoScrolling
    };
};

exports.default = setup();