2020-04-10 15:23:01 -04:00

25 lines
804 B
TypeScript

import { ElementWithTransition } from '../components/Transition'
// compiler should normalize class + :class bindings on the same element
// into a single binding ['staticClass', dynamic]
export function patchClass(el: Element, value: string | null, isSVG: boolean) {
if (value == null) {
value = ''
}
if (isSVG) {
el.setAttribute('class', value)
} else {
// directly setting className should be faster than setAttribute in theory
// if this is an element during a transition, take the temporary transition
// classes into account.
const transitionClasses = (el as ElementWithTransition)._vtc
if (transitionClasses) {
value = (value
? [value, ...transitionClasses]
: [...transitionClasses]
).join(' ')
}
el.className = value
}
}