@lembdev/typeorm-filters-converter

This lib is intended to be used for converting filters in the context of SQL-based debate repositories (e.g. TypeORM ones). Particularly, it helps in the creation of filter conditions for using with repository queries and query builders in TypeORM. It also provides ways to handle global filters which are applied to all other filters.

Table of Contents

1. Constructor
2. setFilters
3. getFilters
4. addFilters
5. setGlobalFilter
6. toRepositoryConditions
7. toQueryBuilderConditions
8. getAffectedColumns
9. getAffectedRepositoryRelations

Constructor

constructor(
  filters?: IFilter<T> | IFilter<T>[],
  fieldMapping?: Map<string, string>
)

Creates an instance of filters converter. Takes filters and field mapping as inputs. Filters could either be a single filter or an array of them.

setFilters

setFilters(filters: IFilter<T> | IFilter<T>[]): void

Resets the existing filters and sets the new filters. The new filters can be either a single filter or an array of filters. getFilters

Examples:

const converter = new FiltersConverter();
converter.setFilters({ id: { eq: 1 } });

const converter = new FiltersConverter();
converter.setFilters([{ id: { eq: 1 } }, { id: { eq: 2 } }]);

getFilters

getFilters(): IFilter<T>[]

Returns the filters that are currently being applied, as an array of individual filters.

Examples:

const converter = new FiltersConverter();
converter.setFilters({ id: { eq: 1 } });
converter.setGlobalFilter({ age: { gte: 19 } });
converter.getFilters(); // [{ id: { eq: 1 }, age: { gte: 19 } }]

addFilters

addFilters(filters?: IFilter<T> | IFilter<T>[]): this

Adds more filters without resetting the previously set filters. These new filters can be either a single filter or an array of filters.

Examples:

const converter = new FiltersConverter();
converter.setFilters({ name: { eq: 'Sam' } });
converter.addFilters({ age: { gte: 19 } });
converter.getFilters(); // [{ name: { eq: 'Sam' } }, { age: { gte: 19 } }]

setGlobalFilter

setGlobalFilter(filters?: IFilter<T>): this

Sets a global filter that gets applied to every filter in the filter set.

Examples:

const converter = new FiltersConverter();
converter.setFilters([{ name: { eq: 'Sam' } }, { name: { eq: 'Alex' } }]);
converter.setGlobalFilter({ age: { gte: 19 } });
// same as
converter.setFilters([
  { name: { eq: 'Sam' }, age: { gte: 19 } },
  { name: { eq: 'Alex' }, age: { gte: 19 } },
]);

const converter = new FiltersConverter();
converter.setFilters([{ name: { eq: 'Sam' } }, { name: { eq: 'Alex' } }]);
converter.setGlobalFilter({ age: { gte: 19 } });
converter.setGlobalFilter({ sex: { eq: 'male' } });
// same as
converter.setFilters([
  { name: { eq: 'Sam' }, age: { gte: 19 }, sex: { eq: 'male' } },
  { name: { eq: 'Alex' }, age: { gte: 19 }, sex: { eq: 'male' } },
]);

toRepositoryConditions

toRepositoryConditions(): FindConditions<T>[]

Transforms the filters to a format that can be handled by TypeORM repositories for filtering purposes.

Examples:

const converter = new FiltersConverter();
converter.setFilters({ name: { eq: 'Sam' } });

const users = await this.userRepository.find({
  where: converter.toRepositoryConditions(),
});

toQueryBuilderConditions

toQueryBuilderConditions(): Brackets

Transforms the filters into a format that can be handled by TypeORM's QueryBuilder.

Examples:

const converter = new FiltersConverter();
converter.setFilters({ name: { eq: 'Sam' } });

const users = await this.dataSource
  .createQueryBuilder()
  .select()
  .from('users', 'user')
  .where(converter.toQueryBuilderConditions())
  .getRawMany();

getAffectedColumns

getAffectedColumns(): string[]

Returns an array containing the names of the columns that have been affected by the filter conditions.

getAffectedRepositoryRelations

getAffectedRepositoryRelations(repository: Repository<T>): string[]

Returns an array containing the names of the relations that have been affected by the filter conditions, based on the given repository.