bootstrap-vue · jacobmllr95 · Nov 15, 2019 · Nov 14, 2019 · Nov 14, 2019 · Nov 14, 2019
diff --git a/src/components/table/helpers/mixin-tbody-row.js b/src/components/table/helpers/mixin-tbody-row.js
@@ -69,17 +69,19 @@ export default {
     rowHovered(evt) {
       // `mouseenter` handler (non-bubbling)
       // `this.tbodyRowEvtStopped` from tbody mixin
-      if (!this.tbodyRowEvtStopped(evt)) {
+      const type = 'row-hovered'
+      if (this.$listeners[type] && !this.tbodyRowEvtStopped(evt)) {
         // `this.emitTbodyRowEvent` from tbody mixin
-        this.emitTbodyRowEvent('row-hovered', evt)
+        this.emitTbodyRowEvent(type, evt)
       }
     },
     rowUnhovered(evt) {
       // `mouseleave` handler (non-bubbling)
       // `this.tbodyRowEvtStopped` from tbody mixin
-      if (!this.tbodyRowEvtStopped(evt)) {
+      const type = 'row-unhovered'
+      if (this.$listeners[type] && !this.tbodyRowEvtStopped(evt)) {
         // `this.emitTbodyRowEvent` from tbody mixin
-        this.emitTbodyRowEvent('row-unhovered', evt)
+        this.emitTbodyRowEvent(type, evt)
       }
     },
     // Render helpers

diff --git a/src/components/table/helpers/mixin-tbody.js b/src/components/table/helpers/mixin-tbody.js
@@ -24,13 +24,12 @@ export default {
       // `this.$refs.itemRows` is an array of item TR components/elements
       // Rows should all be B-TR components, but we map to TR elements
       // Also note that `this.$refs.itemRows` may not always be in document order
-      const tbody = this.$refs.tbody.$el || this.$refs.tbody
-      const trs = (this.$refs.itemRows || []).map(tr => tr.$el || tr)
-      // TODO: This may take time for tables many rows, so we may want to cache
-      //       the result of this during each render cycle on a non-reactive
-      //       property. We clear out the cache as each render starts, and
-      //       populate it on first access of this method if null
-      return arrayFrom(tbody.children).filter(tr => arrayIncludes(trs, tr))
+      const refs = this.$refs || {}
+      const tbody = refs.tbody ? refs.tbody.$el || refs.tbody : null
+      const trs = (refs.itemRows || []).map(tr => tr.$el || tr)
+      return tbody && tbody.children && tbody.children.length > 0 && trs && trs.length > 0
+        ? arrayFrom(tbody.children).filter(tr => arrayIncludes(trs, tr))
+        : []
     },
     getTbodyTrIndex(el) {
       // Returns index of a particular TBODY item TR
@@ -102,6 +101,7 @@ export default {
       }
     },
     onTBodyRowClicked(evt) {
+      // Row-clicked handler is only added when needed
       if (this.tbodyRowEvtStopped(evt)) {
         // If table is busy, then don't propagate
         return
@@ -113,18 +113,21 @@ export default {
       this.emitTbodyRowEvent('row-clicked', evt)
     },
     onTbodyRowMiddleMouseRowClicked(evt) {
-      if (!this.tbodyRowEvtStopped(evt) && evt.which === 2) {
-        this.emitTbodyRowEvent('row-middle-clicked', evt)
+      const type = 'row-middle-clicked'
+      if (this.$listeners[type] && !this.tbodyRowEvtStopped(evt) && evt.which === 2) {
+        this.emitTbodyRowEvent(type, evt)
       }
     },
     onTbodyRowContextmenu(evt) {
-      if (!this.tbodyRowEvtStopped(evt)) {
-        this.emitTbodyRowEvent('row-contextmenu', evt)
+      const type = 'row-contextmenu'
+      if (this.$listeners[type] && !this.tbodyRowEvtStopped(evt)) {
+        this.emitTbodyRowEvent(type, evt)
       }
     },
     onTbodyRowDblClicked(evt) {
-      if (!this.tbodyRowEvtStopped(evt) && !filterEvent(evt)) {
-        this.emitTbodyRowEvent('row-dblclicked', evt)
+      const type = 'row-dblclicked'
+      if (this.$listeners[type] && !this.tbodyRowEvtStopped(evt) && !filterEvent(evt)) {
+        this.emitTbodyRowEvent(type, evt)
       }
     },
     // Note: Row hover handlers are handled by the tbody-row mixin
@@ -187,22 +190,24 @@ export default {
         $rows.push(this.renderBottomRow ? this.renderBottomRow() : h())
       }
 
+      // Note: these events will only emit if a listener is registered
       const handlers = {
-        // TODO: We may want to to only instantiate these handlers
-        //       if there is an event listener registered
         auxclick: this.onTbodyRowMiddleMouseRowClicked,
-        // TODO: Perhaps we do want to automatically prevent the
-        //       default context menu from showing if there is
-        //       a `row-contextmenu` listener registered.
+        // TODO:
+        //   Perhaps we do want to automatically prevent the
+        //   default context menu from showing if there is a
+        //   `row-contextmenu` listener registered
         contextmenu: this.onTbodyRowContextmenu,
         // The following event(s) is not considered A11Y friendly
         dblclick: this.onTbodyRowDblClicked
-        // hover events (mouseenter/mouseleave) ad handled by tbody-row mixin
+        // Hover events (`mouseenter`/`mouseleave`) are handled by `tbody-row` mixin
       }
+      // Add in click/keydown listeners if needed
       if (hasRowClickHandler) {
         handlers.click = this.onTBodyRowClicked
         handlers.keydown = this.onTbodyRowKeydown
       }
+
       // Assemble rows into the tbody
       const $tbody = h(
         BTbody,

diff --git a/src/components/table/table-tbody-row-events.spec.js b/src/components/table/table-tbody-row-events.spec.js
@@ -82,6 +82,10 @@ describe('table > tbody row events', () => {
       propsData: {
         fields: testFields,
         items: testItems
+      },
+      listeners: {
+        // Row-dblclicked will only occur if there is a registered listener
+        'row-dblclicked': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -104,6 +108,10 @@ describe('table > tbody row events', () => {
         fields: testFields,
         items: testItems,
         busy: true
+      },
+      listeners: {
+        // Row-dblclicked will only occur if there is a registered listener
+        'row-dblclicked': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -121,6 +129,10 @@ describe('table > tbody row events', () => {
       propsData: {
         fields: testFields,
         items: testItems
+      },
+      listeners: {
+        // Row-middle-clicked will only occur if there is a registered listener
+        'row-middle-clicked': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -143,6 +155,10 @@ describe('table > tbody row events', () => {
         fields: testFields,
         items: testItems,
         busy: true
+      },
+      listeners: {
+        // Row-middle-clicked will only occur if there is a registered listener
+        'row-middle-clicked': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -160,6 +176,10 @@ describe('table > tbody row events', () => {
       propsData: {
         fields: testFields,
         items: testItems
+      },
+      listeners: {
+        // Row-contextmenu will only occur if there is a registered listener
+        'row-contextmenu': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -182,6 +202,10 @@ describe('table > tbody row events', () => {
         fields: testFields,
         items: testItems,
         busy: true
+      },
+      listeners: {
+        // Row-contextmenu will only occur if there is a registered listener
+        'row-contextmenu': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -199,6 +223,10 @@ describe('table > tbody row events', () => {
       propsData: {
         fields: testFields,
         items: testItems
+      },
+      listeners: {
+        // Row-hovered will only occur if there is a registered listener
+        'row-hovered': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -215,12 +243,33 @@ describe('table > tbody row events', () => {
     wrapper.destroy()
   })
 
+  it('should not emit row-hovered event when a row is hovered and no listener', async () => {
+    const wrapper = mount(BTable, {
+      propsData: {
+        fields: testFields,
+        items: testItems
+      }
+    })
+    expect(wrapper).toBeDefined()
+    const $rows = wrapper.findAll('tbody > tr')
+    expect($rows.length).toBe(3)
+    expect(wrapper.emitted('row-hovered')).not.toBeDefined()
+    $rows.at(1).trigger('mouseenter')
+    expect(wrapper.emitted('row-hovered')).not.toBeDefined()
+
+    wrapper.destroy()
+  })
+
   it('should not emit row-hovered event when a row is hovered and table busy', async () => {
     const wrapper = mount(BTable, {
       propsData: {
         fields: testFields,
         items: testItems,
         busy: true
+      },
+      listeners: {
+        // Row-hovered will only occur if there is a registered listener
+        'row-hovered': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -238,6 +287,10 @@ describe('table > tbody row events', () => {
       propsData: {
         fields: testFields,
         items: testItems
+      },
+      listeners: {
+        // Row-unhovered will only occur if there is a registered listener
+        'row-unhovered': () => {}
       }
     })
     expect(wrapper).toBeDefined()
@@ -254,12 +307,33 @@ describe('table > tbody row events', () => {
     wrapper.destroy()
   })
 
+  it('should not emit row-nhovered event when a row is hovered and no listener', async () => {
+    const wrapper = mount(BTable, {
+      propsData: {
+        fields: testFields,
+        items: testItems
+      }
+    })
+    expect(wrapper).toBeDefined()
+    const $rows = wrapper.findAll('tbody > tr')
+    expect($rows.length).toBe(3)
+    expect(wrapper.emitted('row-unhovered')).not.toBeDefined()
+    $rows.at(1).trigger('mouseleave')
+    expect(wrapper.emitted('row-unhovered')).not.toBeDefined()
+
+    wrapper.destroy()
+  })
+
   it('should not emit row-unhovered event when a row is unhovered and table busy', async () => {
     const wrapper = mount(BTable, {
       propsData: {
         fields: testFields,
         items: testItems,
         busy: true
+      },
+      listeners: {
+        // Row-unhovered will only occur if there is a registered listener
+        'row-unhovered': () => {}
       }
     })
     expect(wrapper).toBeDefined()