Function isCompatEnabled

packages/runtime-core/src/compat/compatConfig.ts:566–588

(
  key: DeprecationTypes,
  instance: ComponentInternalInstance | null,
  enableForBuiltIn = false,
)

}

export function isCompatEnabled(
  key: DeprecationTypes,
  instance: ComponentInternalInstance | null,
  enableForBuiltIn = false,
): boolean {
  // skip compat for built-in components
  if (!enableForBuiltIn && instance && instance.type.__isBuiltIn) {
    return false
  }

  const rawMode = getCompatConfigForKey('MODE', instance) || 2
  const val = getCompatConfigForKey(key, instance)

  const mode = isFunction(rawMode)
    ? rawMode(instance && instance.type)
    : rawMode

  if (mode === 2) {
    return val !== false
  } else {
    return val === true || val === 'suppress-warning'
  }
}

/**
 * Use this for features that are completely removed in non-compat build.