[Tooltip] Tooltips with zero-length texts are never displayed.

Author: wxsms

docs/pages/components/Tooltip.md

@@ -4,6 +4,8 @@
 
 The first element appear in `<tooltip>` node will be the trigger element. You can also use `target` to reference it from outside the component.
 
+**Note**: Tooltips with zero-length texts are never displayed.
+
 Hover over the button below to toggle tooltips.
 
 ```html

src/components/tooltip/Tooltip.vue

@@ -158,22 +158,21 @@
       },
       show () {
         let tooltip = this.$refs.tooltip
-        if (!this.enable || !this.triggerEl || this.isShown()) {
-          return
-        }
-        if (this.timeoutId > 0) {
-          clearTimeout(this.timeoutId)
-          this.timeoutId = 0
-        } else {
-          tooltip.className = `${BASE_CLASS} ${this.placement}`
-          let container = document.querySelector(this.appendTo)
-          container.appendChild(tooltip)
-          utils.setTooltipPosition(tooltip, this.triggerEl, this.placement, this.autoPlacement, this.appendTo)
-          tooltip.offsetHeight
+        if (this.enable && this.triggerEl && this.text && !this.isShown()) {
+          if (this.timeoutId > 0) {
+            clearTimeout(this.timeoutId)
+            this.timeoutId = 0
+          } else {
+            tooltip.className = `${BASE_CLASS} ${this.placement}`
+            let container = document.querySelector(this.appendTo)
+            container.appendChild(tooltip)
+            utils.setTooltipPosition(tooltip, this.triggerEl, this.placement, this.autoPlacement, this.appendTo)
+            tooltip.offsetHeight
+          }
+          utils.addClass(tooltip, SHOW_CLASS)
+          this.$emit('input', true)
+          this.$emit('show')
         }
-        utils.addClass(tooltip, SHOW_CLASS)
-        this.$emit('input', true)
-        this.$emit('show')
       },
       hide () {
         if (this.isShown()) {

test/unit/specs/Tooltip.spec.js

@@ -87,6 +87,26 @@ describe('Tooltip', () => {
     vm.$destroy()
   })
 
+  it('should not show tooltip with empty text', async () => {
+    let res = Vue.compile('<tooltip v-model="show"><button></button></tooltip>')
+    let vm = new Vue({
+      data () {
+        return {
+          show: true
+        }
+      },
+      components: {Tooltip},
+      render: res.render,
+      staticRenderFns: res.staticRenderFns
+    }).$mount()
+    let $el = $(vm.$el)
+    $el.appendTo('body')
+    await utils.sleep(200)
+    expect(document.querySelectorAll('.tooltip').length).to.equal(0)
+    $el.remove()
+    vm.$destroy()
+  })
+
   it('should be able to use custom target', async () => {
     let res = Vue.compile('<div><button ref="btn" type="button">btn</button><tooltip text="test" :target="btn" trigger="focus"></tooltip></div>')
     let vm = new Vue({
@@ -274,7 +294,7 @@ describe('Tooltip', () => {
   })
 
   it('should be able to change trigger in runtime', async () => {
-    let res = Vue.compile('<tooltip :trigger="trigger"><button></button></tooltip>')
+    let res = Vue.compile('<tooltip text="test" :trigger="trigger"><button></button></tooltip>')
     let vm = new Vue({
       data () {
         return {