perf(popover): convert template to render function

src/components/popover/popover.js

@@ -1,3 +1,51 @@
-import bPopover from './popover.vue';
+import PopOver from '../../utils/popover.class';
+import { warn } from '../../utils';
+import { toolpopMixin } from '../../mixins';
 
-export default bPopover;
+export default {
+    mixins: [ toolpopMixin ],
+    render(h) {
+        return h(
+            'div',
+            { class: [ 'd-none' ], style: { display: 'none' }, attrs: { 'aria-hidden': true } },
+            [
+                h('div', { ref: 'title' }, this.$slots.title ),
+                h('div', { ref: 'content' }, this.$slots.default )
+            ]
+        );
+    },
+    data() {
+        return {};
+    },
+    props: {
+        title: {
+            type: String,
+            default: ''
+        },
+        content: {
+            type: String,
+            default: ''
+        },
+        triggers: {
+            type: [String, Array],
+            default: 'click'
+        },
+        placement: {
+            type: String,
+            default: 'right'
+        }
+    },
+    methods: {
+        createToolpop() {
+            // getTarget is in toolpop mixin
+            const target = this.getTarget();
+            if (target) {
+                this._toolpop = new PopOver(target, this.getConfig(), this.$root);
+            } else {
+                this._toolpop = null;
+                warn("b-popover: 'target' element not found!");
+            }
+            return this._toolpop;
+        }
+    }
+};