GraphQL Pagination Implementation

pagination.ts

var graphql = require('graphql');

export function Edge(itemType: any) {
    return new graphql.GraphQLObjectType({
        name: "Edge",
        description: "Generic edge to allow cursors",
        fields: () => ({
            node: { type: itemType },
            cursor: { type: graphql.GraphQLString }
        })
    });
}

export const PageInfo = new graphql.GraphQLObjectType({
    name: "PageInfo",
    description: "Information about current page",
    fields: () => ({
        startCursor: { type: graphql.GraphQLString },
        endCursor: { type: graphql.GraphQLString },
        hasNextPage: { type: graphql.GraphQLBoolean }
    })
});

export function Page(itemType: any) {
    return new graphql.GraphQLObjectType({
        name: "Page",
        description: "Page",
        fields: () => ({
            totalCount: { type: graphql.GraphQLInt },
            edges: { type: new graphql.GraphQLList(Edge(itemType)) },
            pageInfo: { type: PageInfo }
        })
    });
}

export function convertNodeToCursor(node: { id: number }): string {
    return bota(node.id.toString());
}

export function bota(input: string): string {
    return new Buffer(input.toString(), 'binary').toString("base64");
}

export function convertCursorToNodeId(cursor: string): number {
    return parseInt(atob(cursor));
}

export function atob(input: string): string {
    return new Buffer(input, 'base64').toString('binary');
}