ListQueryBuilder
ListQueryBuilder
This helper class is used when fetching entities the database from queries which return a PaginatedList type. These queries all follow the same format:
In the GraphQL definition, they return a type which implements the Node interface, and the query returns a
type which implements the PaginatedList interface:
type BlogPost implements Node {
id: ID!
published: DateTime!
title: String!
body: String!
}
type BlogPostList implements PaginatedList {
items: [BlogPost!]!
totalItems: Int!
}
# Generated at run-time by Vendure
input BlogPostListOptions
extend type Query {
blogPosts(options: BlogPostListOptions): BlogPostList!
}
When Vendure bootstraps, it will find the BlogPostListOptions input and, because it is used in a query
returning a PaginatedList type, it knows that it should dynamically generate this input. This means
all primitive field of the BlogPost type (namely, “published”, “title” and “body”) will have filter and
sort inputs created for them, as well a skip and take fields for pagination.
Your resolver function will then look like this:
@Resolver()
export class BlogPostResolver
constructor(private blogPostService: BlogPostService) {}
@Query()
async blogPosts(
@Ctx() ctx: RequestContext,
@Args() args: any,
): Promise<PaginatedList<BlogPost>> {
return this.blogPostService.findAll(ctx, args.options || undefined);
}
}
and the corresponding service will use the ListQueryBuilder:
@Injectable()
export class BlogPostService {
constructor(private listQueryBuilder: ListQueryBuilder) {}
findAll(ctx: RequestContext, options?: ListQueryOptions<BlogPost>) {
return this.listQueryBuilder
.build(BlogPost, options)
.getManyAndCount()
.then(async ([items, totalItems]) => {
return { items, totalItems };
});
}
}
Signature
class ListQueryBuilder implements OnApplicationBootstrap {
constructor(connection: TransactionalConnection, configService: ConfigService)
build(entity: Type<T>, options: ListQueryOptions<T> = {}, extendedOptions: ExtendedListQueryOptions<T> = {}) => SelectQueryBuilder<T>;
}
Implements
- OnApplicationBootstrap
Members
constructor
(connection: TransactionalConnection, configService: ConfigService) => ListQueryBuilder
build
(entity: Type<T>, options: ListQueryOptions<T> = {}, extendedOptions: ExtendedListQueryOptions<T> = {}) => SelectQueryBuilder<T>
ExtendedListQueryOptions
Options which can be passed to the ListQueryBuilder’s build() method.
Signature
type ExtendedListQueryOptions<T extends VendureEntity> = {
relations?: string[];
channelId?: ID;
where?: FindConditions<T>;
orderBy?: FindOneOptions<T>['order'];
entityAlias?: string;
ctx?: RequestContext;
customPropertyMap?: { [name: string]: string };
}
Members
relations
string[]
channelId
ID
where
FindConditions<T>
orderBy
FindOneOptions<T>['order']
entityAlias
string
T in the generated SQL query.
Defaults to the entity class name lower-cased, i.e. ProductVariant -> 'productvariant'.
ctx
RequestContext
customPropertyMap
{ [name: string]: string }
One of the main tasks of the ListQueryBuilder is to auto-generate filter and sort queries based on the
available columns of a given entity. However, it may also be sometimes desirable to allow filter/sort
on a property of a relation. In this case, the customPropertyMap can be used to define a property
of the options.sort or options.filter which does not correspond to a direct column of the current
entity, and then provide a mapping to the related property to be sorted/filtered.
Example: we want to allow sort/filter by and Order’s customerLastName. The actual lastName property is
not a column in the Order table, it exists on the Customer entity, and Order has a relation to Customer via
Order.customer. Therefore, we can define a customPropertyMap like this:
Example
"""
Manually extend the filter & sort inputs to include the new
field that we want to be able to use in building list queries.
"""
input OrderFilterParameter {
customerLastName: StringOperators
}
input OrderSortParameter {
customerLastName: SortOrder
}
Example
const qb = this.listQueryBuilder.build(Order, options, {
relations: ['customer'],
customPropertyMap: {
// Tell TypeORM how to map that custom
// sort/filter field to the property on a
// related entity.
customerLastName: 'customer.lastName',
},
};
We can now use the customerLastName property to filter or sort
on the list query:
Example
query {
myOrderQuery(options: {
filter: {
customerLastName: { contains: "sm" }
}
}) {
# ...
}
}