<template>
<div class=”search-highlight” v-html=”contentShow”>
</div>
</template>
<script>
const PLUGIN_FLAG = ‘search-hightlight_by_mumaa’
export default {
props: {
content: {
type: String,
default: ''
},
keyword: {
type: String,
default: ''
},
highlightStyle: {
type: String,
default: 'background: #ffff00'
},
currentStyle: {
type: String,
default: 'background: #ff9632'
},
regExp: {
type: Boolean,
default: false
}},
data () {
return {
lightIndex: 0,
matchCount: 0,
contentShow: '',
random: `${Math.random()}`.slice(2)
}},
computed: {
watchString () {return [this.content, this.keyword]
},
watchStyle () {return [this.lightIndex, this.highlightStyle, this.currentStyle]
},
flag () {return `${PLUGIN_FLAG}${this.random}`
},
styleSelector () {return `style[${this.flag}]`
},},
watch: {
watchString: {
immediate: true,
handler () {this.replaceKeywords()
}
},
watchStyle: {
immediate: true,
handler () {this.setStyle()
}
},
lightIndex: {
immediate: true,
handler () {this.$emit('current-change', this.lightIndex)
}
},
matchCount: {
immediate: true,
handler () {this.$emit('match-count-change', this.matchCount)
}
}},
beforeDestroy () {
this.clearStyle()},
methods: {
getTextNodeList (dom) {const nodeList = [...dom.childNodes]
const textNodes = []
while (nodeList.length) {const node = nodeList.shift()
if (node.nodeType === node.TEXT_NODE) {node.wholeText && textNodes.push(node)
} else {nodeList.unshift(...node.childNodes)
}
}
return textNodes
},
getTextInfoList (textNodes) {
let length = 0
const textList = textNodes.map(node => {
let startIdx = length, endIdx = length + node.wholeText.length
length = endIdx
return {
text: node.wholeText,
startIdx,
endIdx
}
})
return textList
},
getMatchList (content, keyword) {if (!this.regExp) {const characters = [...'\\[](){}?.+*^$:|'].reduce((r, c) => (r = true, r), {})
keyword = keyword.split('').map(s => characters[s] ? `\\${s}` : s).join('[\\s\\n]*')
}
const reg = new RegExp(keyword, 'gmi')
const matchList = []
let match = reg.exec(content)
while (match) {matchList.push(match)
match = reg.exec(content)
}
return matchList
},
replaceMatchResult (textNodes, textList, matchList) {
// 对于每一个匹配后果，可能扩散在多个标签中，找出这些标签，截取匹配片段并用 font 标签替换出
for (let i = matchList.length - 1; i >= 0; i--) {const match = matchList[i]
const matchStart = match.index, matchEnd = matchStart + match[0].length // 匹配后果在拼接字符串中的起止索引
// 遍历文本信息列表，查找匹配的文本节点
for (let textIdx = 0; textIdx < textList.length; textIdx++) {const { text, startIdx, endIdx} = textList[textIdx] // 文本内容、文本在拼接串中开始、完结索引
if (endIdx < matchStart) continue // 匹配的文本节点还在前面
if (startIdx >= matchEnd) break // 匹配文本节点曾经解决完了
let textNode = textNodes[textIdx] // 这个节点中的局部或全部内容匹配到了关键词，将匹配局部截取进去进行替换
const nodeMatchStartIdx = Math.max(0, matchStart - startIdx) // 匹配内容在文本节点内容中的开始索引
const nodeMatchLength = Math.min(endIdx, matchEnd) - startIdx - nodeMatchStartIdx // 文本节点内容匹配关键词的长度
if (nodeMatchStartIdx > 0) textNode = textNode.splitText(nodeMatchStartIdx) // textNode 取后半局部
if (nodeMatchLength < textNode.wholeText.length) textNode.splitText(nodeMatchLength)
const font = document.createElement('font')
font.setAttribute(this.flag, i + 1)
font.innerText = text.substr(nodeMatchStartIdx, nodeMatchLength)
textNode.parentNode.replaceChild(font, textNode)
}
}
},
replaceKeywords () {
let flag = false
if (this.regExp) {
try {const reg = new RegExp(this.keyword)
if (reg.test('')) flag = 1
} catch (err) {flag = 1}
}
if (flag || !this.keyword) {
this.contentShow = this.content
return
}
const div = document.createElement('div')
div.innerHTML = this.content
const textNodes = this.getTextNodeList(div)
const textList = this.getTextInfoList(textNodes)
const content = textList.map(({text}) => text).join('')
const matchList = this.getMatchList(content, this.keyword)
this.matchCount = matchList.length
this.lightIndex = this.matchCount ? 1 : 0
this.replaceMatchResult(textNodes, textList, matchList)
this.contentShow = div.innerHTML
},
scrollTo (index) {this.$nextTick(() => {let node = this.$el.querySelector(`font[${this.flag}='${index}']`)
if (node) {
this.lightIndex = index
node.scrollIntoView()}
})
},
searchNext () {this.$nextTick(() => {
let idx = this.lightIndex >= this.matchCount ? 1 : this.lightIndex + 1
this.scrollTo(idx)
})
},
searchLast () {this.$nextTick(() => {
let idx = this.lightIndex <= 1 ? this.matchCount : this.lightIndex - 1
this.scrollTo(idx)
})
},
setStyle () {let style = document.head.querySelector(this.styleSelector)
if (!style) {style = document.createElement('style')
style.setAttribute(this.flag, 1)
}
style.innerText = `font[${this.flag}]{${this.highlightStyle}}font[${this.flag}='${this.lightIndex}']{${this.currentStyle}}`
document.head.appendChild(style)
},
clearStyle () {let style = document.head.querySelector(this.styleSelector)
style && document.head.removeChild(style)
}}
}
</script>