[GraphQL] Use GraphQLList with GraphQLObject Types

GraphQL列表类型实践

最新推荐文章于 2024-02-08 08:59:05 发布

转载最新推荐文章于 2024-02-08 08:59:05 发布 · 160 阅读

本文介绍如何使用GraphQLList从graphql包中结合GraphQLObject类型创建返回集合字段的模式。演示了如何通过GraphQLList获取列表对象，包括定义模式、解析器以及数据获取方法。

When working with collections of things in GraphQL, we'll always reach out for the GraphQLListType. In this video, we'll learn how to use GraphQLList from the graphql package in combination with a GraphQLObject Type to create a field that returns a collection in our Schema.

We can use GraphQLList to fetch list objects:

const queryType = new GraphQLObjectType({
    name: 'QueryType',
    description: 'The root query type',
    fields :{
        videos: {
            type: new GraphQLList(videoType),
            resolve: getVideos
        },
        video: {
            type: videoType,
            args: {
                id: {
                    type : new GraphQLNonNull(GraphQLID),
                    description: 'The id of the video'
                }
            },
            resolve: (_, args) => getVideoById(args.id)
        }
    }
});

Data:

const videoA = {
    id: 'a',
    title: 'Create a GraphQL Schema',
    duration: 120,
    watched: true,
};
const videoB = {
    id: 'b',
    title: 'Ember.js CLI',
    duration: 240,
    watched: false,
};
const videos = [videoA, videoB];
const getVideoById = (id) => new Promise((resolve) => {
    const [video] = videos.filter((video) => {
        return video.id === id;
    });

    resolve(video);
});

const getVideos = () => new Promise((resolve) => resolve(videos));

exports.getVideoById = getVideoById;
exports.getVideos = getVideos;