Function patchAttr

packages/runtime-dom/src/modules/attrs.ts:16–47

(
  el: Element,
  key: string,
  value: any,
  isSVG: boolean,
  instance?: ComponentInternalInstance | null,
  isBoolean: boolean = isSpecialBooleanAttr(key),
)

export const xlinkNS = 'http://www.w3.org/1999/xlink'

export function patchAttr(
  el: Element,
  key: string,
  value: any,
  isSVG: boolean,
  instance?: ComponentInternalInstance | null,
  isBoolean: boolean = isSpecialBooleanAttr(key),
): void {
  if (isSVG && key.startsWith('xlink:')) {
    if (value == null) {
      el.removeAttributeNS(xlinkNS, key.slice(6, key.length))
    } else {
      el.setAttributeNS(xlinkNS, key, value)
    }
  } else {
    if (__COMPAT__ && compatCoerceAttr(el, key, value, instance)) {
      return
    }

    // note we are only checking boolean attributes that don't have a
    // corresponding dom prop of the same name here.
    if (value == null || (isBoolean && !includeBooleanAttr(value))) {
      el.removeAttribute(key)
    } else {
      // attribute value is a string https://html.spec.whatwg.org/multipage/dom.html#attributes
      el.setAttribute(
        key,
        isBoolean ? '' : isSymbol(value) ? String(value) : value,
      )
    }
  }
}

// 2.x compat
const isEnumeratedAttr = __COMPAT__