perf(tooltip): convert template to render function (#1310)

* [tooltip] convert to render function

* Delete tooltip.vue

src/components/tooltip/tooltip.js

@@ -1,3 +1,44 @@
-import bTooltip from './tooltip.vue';
+import ToolTip from '../../utils/tooltip.class';
+import { warn } from '../../utils';
+import { toolpopMixin } from '../../mixins';
 
-export default bTooltip;
+export default {
+    mixins: [ toolpopMixin ],
+    render(h) {
+        return h(
+            'div',
+            { class: [ 'd-none' ], style: { display: 'none' }, attrs: { 'aria-hidden': true } },
+            [ h('div', { ref: 'title' }, this.$slots.default) ]
+        );
+    },
+    data() {
+        return {};
+    },
+    props: {
+        title: {
+            type: String,
+            default: ''
+        },
+        triggers: {
+            type: [String, Array],
+            default: 'hover focus'
+        },
+        placement: {
+            type: String,
+            default: 'top'
+        }
+    },
+    methods: {
+        createToolpop() {
+            // getTarget is in toolpop mixin
+            const target = this.getTarget();
+            if (target) {
+                this._toolpop = new ToolTip(target, this.getConfig(), this.$root);
+            } else {
+                this._toolpop = null;
+                warn("b-tooltip: 'target' element not found!");
+            }
+            return this._toolpop;
+        }
+    }
+};