TypeScript utils.wrap函數代碼示例

function giveMethodSuper(
  obj: object,
  key: string,
  method: Function,
  values: { [key: string]: any },
  descs: { [key: string]: any }
) {
  // Methods overwrite computed properties, and do not call super to them.
  if (descs[key] !== undefined) {
    return method;
  }

  // Find the original method in a parent mixin
  let superMethod = values[key];

  // If we didn't find the original value in a parent mixin, find it in
  // the original object
  if (superMethod === undefined && descriptorFor(obj, key) === undefined) {
    superMethod = obj[key];
  }

  // Only wrap the new method if the original method was a function
  if (typeof superMethod === 'function') {
    return wrap(method, superMethod);
  }

  return method;
}

function giveDescriptorSuper(
  meta: Meta,
  key: string,
  property: ComputedProperty,
  values: { [key: string]: any },
  descs: { [key: string]: any },
  base: object
): ComputedProperty {
  let superProperty;

  // Computed properties override methods, and do not call super to them
  if (values[key] === undefined) {
    // Find the original descriptor in a parent mixin
    superProperty = descs[key];
  }

  // If we didn't find the original descriptor in a parent mixin, find
  // it on the original object.
  if (!superProperty) {
    superProperty = descriptorFor(base, key, meta);
  }

  if (superProperty === undefined || !(superProperty instanceof ComputedProperty)) {
    return property;
  }

  // Since multiple mixins may inherit from the same parent, we need
  // to clone the computed property so that other mixins do not receive
  // the wrapped version.
  property = Object.create(property);
  property._getter = wrap(property._getter, superProperty._getter) as ComputedPropertyGetter;
  if (superProperty._setter) {
    if (property._setter) {
      property._setter = wrap(property._setter, superProperty._setter) as ComputedPropertySetter;
    } else {
      property._setter = superProperty._setter;
    }
  }

  return property;
}

function giveDecoratorSuper(
  meta: Meta,
  key: string,
  decorator: ComputedDecorator,
  values: { [key: string]: any },
  descs: { [key: string]: any },
  base: object
): ComputedDecorator {
  let property = descriptorForDecorator(decorator)!;
  let superProperty;

  if (!(property instanceof ComputedProperty) || property._getter === undefined) {
    return decorator;
  }

  // Computed properties override methods, and do not call super to them
  if (values[key] === undefined) {
    // Find the original descriptor in a parent mixin
    superProperty = descriptorForDecorator(descs[key]);
  }

  // If we didn't find the original descriptor in a parent mixin, find
  // it on the original object.
  if (!superProperty) {
    superProperty = descriptorForProperty(base, key, meta);
  }

  if (superProperty === undefined || !(superProperty instanceof ComputedProperty)) {
    return decorator;
  }

  let get = wrap(property._getter!, superProperty._getter!) as ComputedPropertyGetter;
  let set;

  if (superProperty._setter) {
    if (property._setter) {
      set = wrap(property._setter, superProperty._setter) as ComputedPropertySetter;
    } else {
      // If the super property has a setter, we default to using it no matter what.
      // This is clearly very broken and weird, but it's what was here so we have
      // to keep it until the next major at least.
      //
      // TODO: Add a deprecation here.
      set = superProperty._setter;
    }
  } else {
    set = property._setter;
  }

  // only create a new CP if we must
  if (get !== property._getter || set !== property._setter) {
    // Since multiple mixins may inherit from the same parent, we need
    // to clone the computed property so that other mixins do not receive
    // the wrapped version.
    let newProperty = Object.create(property);
    newProperty._getter = get;
    newProperty._setter = set;

    return makeComputedDecorator(newProperty, ComputedProperty) as ComputedDecorator;
  }

  return decorator;
}