110 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			TypeScript
		
	
	
			
		
		
	
	
			110 lines
		
	
	
		
			2.9 KiB
		
	
	
	
		
			TypeScript
		
	
	
import { App, defineComponent, inject, Transition } from 'vue';
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import classNames from '../_util/classNames';
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import PropTypes from '../_util/vue-types';
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import backTopTypes from './backTopTypes';
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import addEventListener from '../vc-util/Dom/addEventListener';
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import getScroll from '../_util/getScroll';
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import BaseMixin from '../_util/BaseMixin';
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import getTransitionProps from '../_util/getTransitionProps';
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import { defaultConfigProvider } from '../config-provider';
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import scrollTo from '../_util/scrollTo';
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function getDefaultTarget() {
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  return window;
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}
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const props = backTopTypes();
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const BackTop = defineComponent({
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  name: 'ABackTop',
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  inheritAttrs: false,
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  mixins: [BaseMixin],
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  emits: ['click'],
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  props: {
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    ...props,
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    visibilityHeight: PropTypes.number.def(400),
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  },
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  setup() {
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    return {
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      configProvider: inject('configProvider', defaultConfigProvider),
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    };
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  },
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  data() {
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    return {
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      visible: false,
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      scrollEvent: null,
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    };
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  },
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  mounted() {
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    this.$nextTick(() => {
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      const getTarget = this.target || getDefaultTarget;
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      this.scrollEvent = addEventListener(getTarget(), 'scroll', this.handleScroll);
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      this.handleScroll();
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    });
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  },
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  beforeUnmount() {
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    if (this.scrollEvent) {
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      this.scrollEvent.remove();
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    }
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  },
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  methods: {
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    getCurrentScrollTop() {
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      const getTarget = this.target || getDefaultTarget;
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      const targetNode = getTarget();
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      if (targetNode === window) {
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        return window.pageYOffset || document.body.scrollTop || document.documentElement.scrollTop;
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      }
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      return targetNode.scrollTop;
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    },
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    scrollToTop(e: Event) {
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      const { target = getDefaultTarget } = this;
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      scrollTo(0, {
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        getContainer: target,
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      });
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      this.$emit('click', e);
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    },
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    handleScroll() {
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      const { visibilityHeight, target = getDefaultTarget } = this;
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      const scrollTop = getScroll(target(), true);
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      this.setState({
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        visible: scrollTop > visibilityHeight,
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      });
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    },
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  },
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  render() {
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    const { prefixCls: customizePrefixCls, $slots } = this;
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    const getPrefixCls = this.configProvider.getPrefixCls;
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    const prefixCls = getPrefixCls('back-top', customizePrefixCls);
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    const classString = classNames(prefixCls, this.$attrs.class);
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    const defaultElement = (
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      <div class={`${prefixCls}-content`}>
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        <div class={`${prefixCls}-icon`} />
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      </div>
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    );
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    const divProps = {
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      ...this.$attrs,
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      onClick: this.scrollToTop,
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      class: classString,
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    };
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    const backTopBtn = this.visible ? (
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      <div {...divProps}>{($slots.default && $slots.default()) || defaultElement}</div>
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    ) : null;
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    const transitionProps = getTransitionProps('fade');
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    return <Transition {...transitionProps}>{backTopBtn}</Transition>;
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  },
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});
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/* istanbul ignore next */
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BackTop.install = function(app: App) {
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  app.component(BackTop.name, BackTop);
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  return app;
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};
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export default BackTop;
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