const blank = {
|
' ': true,
|
'\n': true,
|
'\t': true,
|
'\r': true,
|
'\f': true
|
}
|
|
function Parser () {
|
this.styles = []
|
this.selectors = []
|
}
|
|
/**
|
* @description 解析 css 字符串
|
* @param {string} content css 内容
|
*/
|
Parser.prototype.parse = function (content) {
|
new Lexer(this).parse(content)
|
return this.styles
|
}
|
|
/**
|
* @description 解析到一个选择器
|
* @param {string} name 名称
|
*/
|
Parser.prototype.onSelector = function (name) {
|
// 不支持的选择器
|
if (name.includes('[') || name.includes('*') || name.includes('@')) return
|
const selector = {}
|
// 伪类
|
if (name.includes(':')) {
|
const info = name.split(':')
|
const pseudo = info.pop()
|
if (pseudo === 'before' || pseudo === 'after') {
|
selector.pseudo = pseudo
|
name = info[0]
|
} else return
|
}
|
|
// 分割交集选择器
|
function splitItem (str) {
|
const arr = []
|
let i, start
|
for (i = 1, start = 0; i < str.length; i++) {
|
if (str[i] === '.' || str[i] === '#') {
|
arr.push(str.substring(start, i))
|
start = i
|
}
|
}
|
if (!arr.length) {
|
return str
|
} else {
|
arr.push(str.substring(start, i))
|
return arr
|
}
|
}
|
|
// 后代选择器
|
if (name.includes(' ')) {
|
selector.list = []
|
const list = name.split(' ')
|
for (let i = 0; i < list.length; i++) {
|
if (list[i].length) {
|
// 拆分子选择器
|
const arr = list[i].split('>')
|
for (let j = 0; j < arr.length; j++) {
|
selector.list.push(splitItem(arr[j]))
|
if (j < arr.length - 1) {
|
selector.list.push('>')
|
}
|
}
|
}
|
}
|
} else {
|
selector.key = splitItem(name)
|
}
|
|
this.selectors.push(selector)
|
}
|
|
/**
|
* @description 解析到选择器内容
|
* @param {string} content 内容
|
*/
|
Parser.prototype.onContent = function (content) {
|
// 并集选择器
|
for (let i = 0; i < this.selectors.length; i++) {
|
this.selectors[i].style = content
|
}
|
this.styles = this.styles.concat(this.selectors)
|
this.selectors = []
|
}
|
|
/**
|
* @description css 词法分析器
|
* @param {object} handler 高层处理器
|
*/
|
function Lexer (handler) {
|
this.selector = ''
|
this.style = ''
|
this.handler = handler
|
}
|
|
Lexer.prototype.parse = function (content) {
|
this.i = 0
|
this.content = content
|
this.state = this.blank
|
for (let len = content.length; this.i < len; this.i++) {
|
this.state(content[this.i])
|
}
|
}
|
|
Lexer.prototype.comment = function () {
|
this.i = this.content.indexOf('*/', this.i) + 1
|
if (!this.i) {
|
this.i = this.content.length
|
}
|
}
|
|
Lexer.prototype.blank = function (c) {
|
if (!blank[c]) {
|
if (c === '/' && this.content[this.i + 1] === '*') {
|
this.comment()
|
return
|
}
|
this.selector += c
|
this.state = this.name
|
}
|
}
|
|
Lexer.prototype.name = function (c) {
|
if (c === '/' && this.content[this.i + 1] === '*') {
|
this.comment()
|
return
|
}
|
if (c === '{' || c === ',' || c === ';') {
|
this.handler.onSelector(this.selector.trimEnd())
|
this.selector = ''
|
if (c !== '{') {
|
while (blank[this.content[++this.i]]);
|
}
|
if (this.content[this.i] === '{') {
|
this.floor = 1
|
this.state = this.val
|
} else {
|
this.selector += this.content[this.i]
|
}
|
} else if (blank[c]) {
|
this.selector += ' '
|
} else {
|
this.selector += c
|
}
|
}
|
|
Lexer.prototype.val = function (c) {
|
if (c === '/' && this.content[this.i + 1] === '*') {
|
this.comment()
|
return
|
}
|
if (c === '{') {
|
this.floor++
|
} else if (c === '}') {
|
this.floor--
|
if (!this.floor) {
|
this.handler.onContent(this.style)
|
this.style = ''
|
this.state = this.blank
|
return
|
}
|
}
|
this.style += c
|
}
|
|
module.exports = Parser
|
