class.ts
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import { isDef, isUndef } from 'shared/util'
import type { VNodeData } from 'types/vnode'
import { concat, stringifyClass, genClassForVnode } from 'web/util/index'
function updateClass(oldVnode: any, vnode: any) {
const el = vnode.elm
const data: VNodeData = vnode.data
const oldData: VNodeData = oldVnode.data
if (
isUndef(data.staticClass) &&
isUndef(data.class) &&
(isUndef(oldData) ||
(isUndef(oldData.staticClass) && isUndef(oldData.class)))
) {
return
}
let cls = genClassForVnode(vnode)
// handle transition classes
const transitionClass = el._transitionClasses
if (isDef(transitionClass)) {
cls = concat(cls, stringifyClass(transitionClass))
}
// set the class
if (cls !== el._prevClass) {
el.setAttribute('class', cls)
el._prevClass = cls
}
}
export default {
create: updateClass,
update: updateClass
}