Function installAppCompatProperties

packages/runtime-core/src/compat/global.ts:332–350

(
  app: App,
  context: AppContext,
  render: RootRenderFunction<any>,
)

}

export function installAppCompatProperties(
  app: App,
  context: AppContext,
  render: RootRenderFunction<any>,
): void {
  installFilterMethod(app, context)
  installLegacyOptionMergeStrats(app.config)

  if (!singletonApp) {
    // this is the call of creating the singleton itself so the rest is
    // unnecessary
    return
  }

  installCompatMount(app, context, render)
  installLegacyAPIs(app)
  applySingletonAppMutations(app)
  if (__DEV__) installLegacyConfigWarnings(app.config)
}

function installFilterMethod(app: App, context: AppContext) {
  context.filters = {}