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| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 | 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 1x 18x 18x 18x 18x 18x 18x 18x 18x 18x 18x 1x 1x 1x | /**
* 平滑滚动到某个元素，只进行垂直方向的滚动
* - requires jQuery/Zepto
* @method fx/smoothScrollTo
* @param {Object} node 目标DOM元素
* @param {Object} spec 选项
* @param {Number} [spec.delta=0] 目标滚动位置与目标元素顶部的间距，可以为负值
* @param {Number} [spec.maxDelay=3000] 动画执行时间限制(ms)，动画执行超过此时间则直接停止，立刻滚动到目标位置
* @param {Function} [options.callback] 滚动完成的回调函数
* @example
* var $smoothScrollTo = require('@spore-ui/kit/packages/fx/smoothScrollTo');
* // 滚动到页面顶端
* $smoothScrollTo(document.body);
*/
var $assign = require('../obj/assign');
function smoothScrollTo(node, spec) {
var $ = window.$ || window.Zepto || window.jQuery;
var conf = $assign({
delta: 0,
maxDelay: 3000,
callback: null,
}, spec);
var offset = $(node).offset();
var target = offset.top + conf.delta;
var callback = conf.callback;
var prevStep;
var stayCount = 3;
var timer = null;
var stopTimer = function () {
Eif (timer) {
clearInterval(timer);
timer = null;
window.scrollTo(0, target);
Eif ($.isFunction(callback)) {
callback();
}
}
};
timer = setInterval(function () {
var sTop = $(window).scrollTop();
var delta = sTop - target;
Iif (delta > 0) {
delta = Math.floor(delta * 0.8);
} else Eif (delta < 0) {
delta = Math.ceil(delta * 0.8);
}
var step = target + delta;
Iif (step === prevStep) {
stayCount -= 1;
}
prevStep = step;
window.scrollTo(0, step);
Iif (step === target || stayCount <= 0) {
stopTimer();
}
}, 16);
setTimeout(function () {
stopTimer();
}, conf.maxDelay);
}
module.exports = smoothScrollTo;
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