Function resolveCssVars

packages/runtime-core/src/hydration.ts:947–969

(
  instance: ComponentInternalInstance,
  vnode: VNode,
  expectedMap: Map<string, string>,
)

}

function resolveCssVars(
  instance: ComponentInternalInstance,
  vnode: VNode,
  expectedMap: Map<string, string>,
) {
  const root = instance.subTree
  if (
    instance.getCssVars &&
    (vnode === root ||
      (root &&
        root.type === Fragment &&
        (root.children as VNode[]).includes(vnode)))
  ) {
    const cssVars = instance.getCssVars()
    for (const key in cssVars) {
      const value = normalizeCssVarValue(cssVars[key])
      expectedMap.set(`--${getEscapedCssVarName(key, false)}`, value)
    }
  }
  if (vnode === root && instance.parent) {
    resolveCssVars(instance.parent, instance.vnode, expectedMap)
  }
}

const allowMismatchAttr = 'data-allow-mismatch'