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| import { VantComponent } from '../common/component';
| import { pageScrollMixin } from '../mixins/page-scroll';
| const ROOT_ELEMENT = '.van-sticky';
| VantComponent({
| props: {
| zIndex: {
| type: Number,
| value: 99,
| },
| offsetTop: {
| type: Number,
| value: 0,
| observer: 'onScroll',
| },
| disabled: {
| type: Boolean,
| observer: 'onScroll',
| },
| container: {
| type: null,
| observer: 'onScroll',
| },
| scrollTop: {
| type: null,
| observer(val) {
| this.onScroll({ scrollTop: val });
| },
| },
| },
| mixins: [
| pageScrollMixin(function (event) {
| if (this.data.scrollTop != null) {
| return;
| }
| this.onScroll(event);
| }),
| ],
| data: {
| height: 0,
| fixed: false,
| transform: 0,
| },
| mounted() {
| this.onScroll();
| },
| methods: {
| onScroll(obj) {
| obj = obj||{}
| let scrollTop = obj.scrollTop
| const { container, offsetTop, disabled } = this.data;
| if (disabled) {
| this.setDataAfterDiff({
| fixed: false,
| transform: 0,
| });
| return;
| }
| this.scrollTop = scrollTop || this.scrollTop;
| if (typeof container === 'function') {
| Promise.all([this.getRect(ROOT_ELEMENT), this.getContainerRect()]).then(
| ([root, container]) => {
| if (offsetTop + root.height > container.height + container.top) {
| this.setDataAfterDiff({
| fixed: false,
| transform: container.height - root.height,
| });
| } else if (offsetTop >= root.top) {
| this.setDataAfterDiff({
| fixed: true,
| height: root.height,
| transform: 0,
| });
| } else {
| this.setDataAfterDiff({ fixed: false, transform: 0 });
| }
| }
| );
| return;
| }
| this.getRect(ROOT_ELEMENT).then((root) => {
| if (offsetTop >= root.top) {
| this.setDataAfterDiff({ fixed: true, height: root.height });
| this.transform = 0;
| } else {
| this.setDataAfterDiff({ fixed: false });
| }
| });
| },
| setDataAfterDiff(data) {
| wx.nextTick(() => {
| const diff = Object.keys(data).reduce((prev, key) => {
| if (data[key] !== this.data[key]) {
| prev[key] = data[key];
| }
| return prev;
| }, {});
| this.setData(diff);
| this.$emit('scroll', {
| scrollTop: this.scrollTop,
| isFixed: data.fixed || this.data.fixed,
| });
| });
| },
| getContainerRect() {
| const nodesRef = this.data.container();
| return new Promise((resolve) =>
| nodesRef.boundingClientRect(resolve).exec()
| );
| },
| },
| });
|
|
