/* 不传入 props 则默认使用当前 props */
updateState ({ location, params: { msgId }, userData: { username }, msg: { msgs } } = this.props) {
// 情况1：处于 /msg/add，直接就是还原初始状态
if (isAddMode(location.pathname)) {
return this.setState(getInitState())
}
// 情况2：处于 /msg/modify/:msgId，且 state 中 msgs 不为空
if (msgs.length) {
let nextState = msgs.filter(({ id }) => id === msgId)[0]
if (!nextState || nextState.author !== username) {
return this.handleIllegal()
}
return this.setState(nextState)
}
// 情况3：强制刷新 /msg/detail/:msgId 后，跳转到 /msg/modify/:msgId
// 此时 state 中 msgs 为空，需要立即从后端 API 获取
msgService.fetch({ msgId }).then(msg => {
let { id, title, content, author } = msg
if (!msg || author !== username) {
return this.handleIllegal()
}
this.setState({ id, title, content })
})
}
fetchMsgFromAPI (msgId) {
msgService.fetch({ msgId }).then(msg => {
if (!msg) return this.context.router.replace('/msg')
this.setState({ msg })
})
}