<template>
<div class="muli-tags" @click='focus'>
 <button class='btn' v-for='(tag, index) in tags' :key='index'>
 {{tag}}
 </button>
 <input type="text" ref='input' v-model='current'>
</div>
</template>

<script>
export default {
 name: 'TagsInput',
 methods: {
 focus () {
 this.$refs.input.focus()
 },
 },
 data () {
 return {
 tags: [],
 current: ''
 }
 }
}
</script>

<style lang='less'>
 .muli-tags{
 padding: 5px 10px;
 display: block;
 border: 1px solid #ccc;
 input{
 background: transparent;
 }
 }
 .btn{
 margin: 0 5px 3px 0;
 padding: 4px 5px;
 background: #fff;
 border: 1px solid #eee;
 box-shadow: 0 0 4px;
 }
</style>

// @keydown.188 188代表是是分号键的keyCode
<input type="text"
 ref='input'
 @keyup.enter="add"
 @keydown.delete="del"
 @keydown.188='split'
 v-model='current'>
 
methods: {
 // 按下分号键的时候，需要阻止默认事件，否则会出现分号
 split (e) {
 e.preventDefault()
 this.add(e)
 },
 add (e) {
 const val = e.target.value
 if (!val) return
 // 如果已经存在相同tag，不再添加
 if (this.tags.indexOf(val) > -1) return
 // 把输入值添加到tag，并清空文本框
 this.tags.push(val)
 this.current = ''
 },
 del (e) {
 // 当文本框内没有值，再按回退键，则删除最后一个tag
 if (!e.target.value.length) {
 this.tags.pop()
 }
 },
} 

<button class='btn' v-for='(tag, index) in tags' :key='index' @click='delTag(index)'>{{tag}} <span>x</span></button>

methods: {
 // 删除点击的标签
 delTag (index) {
 this.tags.splice(index, 1)
 }
}

 // props
 props: {
 value: Array,
 required: true,
 default: () => []
 }
 
 // computed
 computed: {
 tags () {
 return this.value.slice()
 }
 }
 
 // methods
 methods: {
 // 删除点击的标签
 delTag (index) {
 this.tags.splice(index, 1)
 this.$emit('input', this.tags)
 }
 }

// TagsInput.vue
<template>
 <div class="muli-tags" @click='focus'>
 <button class='btn' v-for='(tag, index) in tags' :key='index' @click='delTag(index)'>{{tag}} <span>x</span></button>
 <input type="text"
 ref='input'
 @keyup.enter="add"
 @keydown.delete="del"
 @keydown.188='split'
 v-model='current'>
 </div>
</template>

<script>
export default {
 props: {
 value: Array,
 required: true,
 default: () => []
 },
 methods: {
 focus () {
 this.$refs.input.focus()
 },
 split (e) {
 e.preventDefault()
 this.add(e)
 },
 add (e) {
 const val = e.target.value
 if (!val) return
 if (this.tags.indexOf(val) > -1) return
 this.tags.push(val)
 this.$emit('input', this.tags)
 this.current = ''
 },
 del (e) {
 if (!e.target.value.length) {
 this.tags.pop()
 this.$emit('input', this.tags)
 }
 },
 delTag (index) {
 this.tags.splice(index, 1)
 this.$emit('input', this.tags)
 }
 },
 computed: {
 tags () {
 return this.value.slice()
 }
 },
 data () {
 return {
 current: ''
 }
 }
}
</script>

<style lang='less'>
.muli-tags{
 padding: 5px 10px;
 display: block;
 border: 1px solid #ccc;
 input{
 background: transparent;
 }
 .btn{
 margin: 0 5px 3px 0;
 padding: 4px 5px;
 background: #fff;
 border: 1px solid #eee;
 box-shadow: 0 0 4px;
 }
}
</style>

// 父组件
<template>
 <tags-input v-model='tags'/>
</template>
<script>
import TagsInput from './TagsInput.vue'
export default {
 components: {
 TagsInput
 },
 data () {
 return {
 tags: ['tag1', 'tag2', 'tag3']
 }
 }
}
</script>