vue hello world项目
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 

150 lines
3.1 KiB

let { list } = require('postcss')
let OldSelector = require('./old-selector')
let Prefixer = require('./prefixer')
let Browsers = require('./browsers')
let utils = require('./utils')
class Selector extends Prefixer {
constructor(name, prefixes, all) {
super(name, prefixes, all)
this.regexpCache = new Map()
}
/**
* Is rule selectors need to be prefixed
*/
check(rule) {
if (rule.selector.includes(this.name)) {
return !!rule.selector.match(this.regexp())
}
return false
}
/**
* Return prefixed version of selector
*/
prefixed(prefix) {
return this.name.replace(/^(\W*)/, `$1${prefix}`)
}
/**
* Lazy loadRegExp for name
*/
regexp(prefix) {
if (!this.regexpCache.has(prefix)) {
let name = prefix ? this.prefixed(prefix) : this.name
this.regexpCache.set(
prefix,
new RegExp(`(^|[^:"'=])${utils.escapeRegexp(name)}`, 'gi')
)
}
return this.regexpCache.get(prefix)
}
/**
* All possible prefixes
*/
possible() {
return Browsers.prefixes()
}
/**
* Return all possible selector prefixes
*/
prefixeds(rule) {
if (rule._autoprefixerPrefixeds) {
if (rule._autoprefixerPrefixeds[this.name]) {
return rule._autoprefixerPrefixeds
}
} else {
rule._autoprefixerPrefixeds = {}
}
let prefixeds = {}
if (rule.selector.includes(',')) {
let ruleParts = list.comma(rule.selector)
let toProcess = ruleParts.filter(el => el.includes(this.name))
for (let prefix of this.possible()) {
prefixeds[prefix] = toProcess
.map(el => this.replace(el, prefix))
.join(', ')
}
} else {
for (let prefix of this.possible()) {
prefixeds[prefix] = this.replace(rule.selector, prefix)
}
}
rule._autoprefixerPrefixeds[this.name] = prefixeds
return rule._autoprefixerPrefixeds
}
/**
* Is rule already prefixed before
*/
already(rule, prefixeds, prefix) {
let index = rule.parent.index(rule) - 1
while (index >= 0) {
let before = rule.parent.nodes[index]
if (before.type !== 'rule') {
return false
}
let some = false
for (let key in prefixeds[this.name]) {
let prefixed = prefixeds[this.name][key]
if (before.selector === prefixed) {
if (prefix === key) {
return true
} else {
some = true
break
}
}
}
if (!some) {
return false
}
index -= 1
}
return false
}
/**
* Replace selectors by prefixed one
*/
replace(selector, prefix) {
return selector.replace(this.regexp(), `$1${this.prefixed(prefix)}`)
}
/**
* Clone and add prefixes for at-rule
*/
add(rule, prefix) {
let prefixeds = this.prefixeds(rule)
if (this.already(rule, prefixeds, prefix)) {
return
}
let cloned = this.clone(rule, { selector: prefixeds[this.name][prefix] })
rule.parent.insertBefore(rule, cloned)
}
/**
* Return function to fast find prefixed selector
*/
old(prefix) {
return new OldSelector(this, prefix)
}
}
module.exports = Selector