@kangc/v-md-editor/src/components/scrollbar/bar.js

A markdown editor built on Vue

// Modified from https://github.com/ElemeFE/element/tree/dev/packages/scrollbar

import { renderThumbStyle, BAR_MAP } from './util';

/* istanbul ignore next */
export default {
  name: 'Bar',

  props: {
    vertical: Boolean,
    size: String,
    move: Number,
  },

  computed: {
    bar() {
      return BAR_MAP[this.vertical ? 'vertical' : 'horizontal'];
    },

    wrap() {
      return this.$parent.wrap;
    },
  },

  render() {
    const { size, move, bar } = this;

    return (
      <div
        class={['scrollbar__bar', 'is-' + bar.key]}
        onMousedown={this.clickTrackHandler}
        onClick={(e) => e.stopPropagation()}
      >
        <div
          ref="thumb"
          class="scrollbar__thumb"
          onMousedown={this.clickThumbHandler}
          style={renderThumbStyle({ size, move, bar })}
        ></div>
      </div>
    );
  },

  methods: {
    clickThumbHandler(e) {
      // prevent click event of right button
      if (e.ctrlKey || e.button === 2) {
        return;
      }
      this.startDrag(e);
      this[this.bar.axis] =
        e.currentTarget[this.bar.offset] -
        (e[this.bar.client] - e.currentTarget.getBoundingClientRect()[this.bar.direction]);
    },

    clickTrackHandler(e) {
      const offset = Math.abs(
        e.target.getBoundingClientRect()[this.bar.direction] - e[this.bar.client]
      );
      const thumbHalf = this.$refs.thumb[this.bar.offset] / 2;
      const thumbPositionPercentage = ((offset - thumbHalf) * 100) / this.$el[this.bar.offset];

      this.wrap[this.bar.scroll] = (thumbPositionPercentage * this.wrap[this.bar.scrollSize]) / 100;
    },

    startDrag(e) {
      e.stopImmediatePropagation();
      this.cursorDown = true;

      document.addEventListener('mousemove', this.mouseMoveDocumentHandler, false);
      document.addEventListener('mouseup', this.mouseUpDocumentHandler, false);
      document.onselectstart = () => false;
    },

    mouseMoveDocumentHandler(e) {
      if (this.cursorDown === false) return;
      const prevPage = this[this.bar.axis];

      if (!prevPage) return;

      const offset =
        (this.$el.getBoundingClientRect()[this.bar.direction] - e[this.bar.client]) * -1;
      const thumbClickPosition = this.$refs.thumb[this.bar.offset] - prevPage;
      const thumbPositionPercentage =
        ((offset - thumbClickPosition) * 100) / this.$el[this.bar.offset];

      this.wrap[this.bar.scroll] = (thumbPositionPercentage * this.wrap[this.bar.scrollSize]) / 100;
    },

    mouseUpDocumentHandler() {
      this.cursorDown = false;
      this[this.bar.axis] = 0;
      document.removeEventListener('mousemove', this.mouseMoveDocumentHandler, false);
      document.onselectstart = null;
    },
  },

  destroyed() {
    document.removeEventListener('mouseup', this.mouseUpDocumentHandler, false);
  },
};