Fix/popover performance

src/components/popover/popover.js

@@ -0,0 +1,156 @@
+
+const Popover = {
+  name: 'Popover',
+  props: {
+    // Action to trigger popover: either 'hover' or 'click'
+    trigger: String,
+    // Either 'top' or 'bottom'
+    placement: String,
+    // Takes object with properties 'x' and 'y', values of these can be
+    // 'container' for using offsetParent as boundaries for either axis
+    // or 'viewport'
+    boundTo: Object,
+    // Takes a top/bottom/left/right object, how much space to leave
+    // between boundary and popover element
+    margin: Object,
+    // Takes a x/y object and tells how many pixels to offset from
+    // anchor point on either axis
+    offset: Object,
+    // Additional styles you may want for the popover container
+    popoverClass: String
+  },
+  data () {
+    return {
+      hidden: true,
+      styles: { opacity: 0 },
+      oldSize: { width: 0, height: 0 }
+    }
+  },
+  methods: {
+    updateStyles () {
+      if (this.hidden) {
+        this.styles = {
+          opacity: 0
+        }
+        return
+      }
+
+      // Popover will be anchored around this element, trigger ref is the container, so
+      // its children are what are inside the slot. Expect only one slot="trigger".
+      const anchorEl = (this.$refs.trigger && this.$refs.trigger.children[0]) || this.$el
+      const screenBox = anchorEl.getBoundingClientRect()
+      // Screen position of the origin point for popover
+      const origin = { x: screenBox.left + screenBox.width * 0.5, y: screenBox.top }
+      const content = this.$refs.content
+      // Minor optimization, don't call a slow reflow call if we don't have to
+      const parentBounds = this.boundTo &&
+        (this.boundTo.x === 'container' || this.boundTo.y === 'container') &&
+        this.$el.offsetParent.getBoundingClientRect()
+      const margin = this.margin || {}
+
+      // What are the screen bounds for the popover? Viewport vs container
+      // when using viewport, using default margin values to dodge the navbar
+      const xBounds = this.boundTo && this.boundTo.x === 'container' ? {
+        min: parentBounds.left + (margin.left || 0),
+        max: parentBounds.right - (margin.right || 0)
+      } : {
+        min: 0 + (margin.left || 10),
+        max: window.innerWidth - (margin.right || 10)
+      }
+
+      const yBounds = this.boundTo && this.boundTo.y === 'container' ? {
+        min: parentBounds.top + (margin.top || 0),
+        max: parentBounds.bottom - (margin.bottom || 0)
+      } : {
+        min: 0 + (margin.top || 50),
+        max: window.innerHeight - (margin.bottom || 5)
+      }
+
+      let horizOffset = 0
+
+      // If overflowing from left, move it so that it doesn't
+      if ((origin.x - content.offsetWidth * 0.5) < xBounds.min) {
+        horizOffset += -(origin.x - content.offsetWidth * 0.5) + xBounds.min
+      }
+
+      // If overflowing from right, move it so that it doesn't
+      if ((origin.x + horizOffset + content.offsetWidth * 0.5) > xBounds.max) {
+        horizOffset -= (origin.x + horizOffset + content.offsetWidth * 0.5) - xBounds.max
+      }
+
+      // Default to whatever user wished with placement prop
+      let usingTop = this.placement !== 'bottom'
+
+      // Handle special cases, first force to displaying on top if there's not space on bottom,
+      // regardless of what placement value was. Then check if there's not space on top, and
+      // force to bottom, again regardless of what placement value was.
+      if (origin.y + content.offsetHeight > yBounds.max) usingTop = true
+      if (origin.y - content.offsetHeight < yBounds.min) usingTop = false
+
+      const yOffset = (this.offset && this.offset.y) || 0
+      const translateY = usingTop
+        ? -anchorEl.offsetHeight - yOffset - content.offsetHeight
+        : yOffset
+
+      const xOffset = (this.offset && this.offset.x) || 0
+      const translateX = (anchorEl.offsetWidth * 0.5) - content.offsetWidth * 0.5 + horizOffset + xOffset
+
+      // Note, separate translateX and translateY avoids blurry text on chromium,
+      // single translate or translate3d resulted in blurry text.
+      this.styles = {
+        opacity: 1,
+        transform: `translateX(${Math.floor(translateX)}px) translateY(${Math.floor(translateY)}px)`
+      }
+    },
+    showPopover () {
+      if (this.hidden) this.$emit('show')
+      this.hidden = false
+      this.$nextTick(this.updateStyles)
+    },
+    hidePopover () {
+      if (!this.hidden) this.$emit('close')
+      this.hidden = true
+      this.styles = { opacity: 0 }
+    },
+    onMouseenter (e) {
+      if (this.trigger === 'hover') this.showPopover()
+    },
+    onMouseleave (e) {
+      if (this.trigger === 'hover') this.hidePopover()
+    },
+    onClick (e) {
+      if (this.trigger === 'click') {
+        if (this.hidden) {
+          this.showPopover()
+        } else {
+          this.hidePopover()
+        }
+      }
+    },
+    onClickOutside (e) {
+      if (this.hidden) return
+      if (this.$el.contains(e.target)) return
+      this.hidePopover()
+    }
+  },
+  updated () {
+    // Monitor changes to content size, update styles only when content sizes have changed,
+    // that should be the only time we need to move the popover box if we don't care about scroll
+    // or resize
+    const content = this.$refs.content
+    if (!content) return
+    if (this.oldSize.width !== content.offsetWidth || this.oldSize.height !== content.offsetHeight) {
+      this.updateStyles()
+      this.oldSize = { width: content.offsetWidth, height: content.offsetHeight }
+    }
+  },
+  created () {
+    document.addEventListener('click', this.onClickOutside)
+  },
+  destroyed () {
+    document.removeEventListener('click', this.onClickOutside)
+    this.hidePopover()
+  }
+}
+
+export default Popover