GraphQL Pagination / MongoDB

Module provides MongoDB DataSource for Graphql Pagination.

Usage

Choose which MongoDb collection field are you going to paginate on. If it's default _id it's expected that is mongo's ObjectId type and needs conversion from string to it via provided ObjectIdCursorEncoderDecoder. Otherwise you don't need to provide cursor and let default cursor decode the cursor.

Initialize the MongoDbDataSource with following config and pass it to dataSourcePager like any other. Use filters to provide additional filtering logic if needed.

import { MongoDbDataSource, ObjectIdCursorEncoderDecoder } from "@graphql-pagination/mongodb";

const mongoDb = mongoClient.db("data");
const dataSource = new MongoDbDataSource<BookType, ObjectId, QueryBooksArgs, QueryBooks_DescArgs>({
    collectionName: "book",
    mongoDb,
    filters: (args) => {
        const filters = [];
        if (args.author) filters.push({ "author": { $eq: args.author } });
        return filters;
    },
});

const cursor = new ObjectIdCursorEncoderDecoder();
// Create pager ideally `dataSourceLoaderPager` within context creation to get benefit of memoization.
// For long lived pager use `dataSourcePager`.
const booksPager = dataSourceLoaderPager({ 
    dataSource, 
    cursor, 
    fetchTotalCountInResolver: false 
    typeName: "Book",
}),

Offset Pagination

If you want to use MongoDb's skip (offset) pagination, you can use MongoDbOffsetDataSource instead of MongoDbDataSource. Implementation also provides sortBy feature.

For offset translation to cursor, it's needed to use OffsetDataSourceWrapper to wrap MongoDbOffsetDataSource.

import { MongoDbOffsetDataSource } from "@graphql-pagination/mongodb";

const mongoDb = mongoClient.db("data");
const ds = new MongoDbOffsetDataSource<BookType, QueryBooksArgs, QueryBooks_DescArgs>({
    collectionName: "book",
    mongoDb,
    filters: (args) => {
        const filters = [];
        if (args.author) filters.push({ "author": { $eq: args.author } });
        return filters;
    },
});
// Always wrap DS with OffsetDataSourceWrapper
const dataSource = new OffsetDataSourceWrapper(ds);

// Create pager ideally `dataSourceLoaderPager` within context creation to get benefit of memoization.
// For long lived pager use `dataSourcePager`.
const booksOffsetPager = dataSourceLoaderPager({ 
    dataSource, 
    fetchTotalCountInResolver: false 
    typeName: "Book",
}),

See fully working example in examples/mongodb.