Question

我尝试练习一些GrahpQL，但被困住了... 我想从api列表中获取一个对象，但是grahpql返回null。用过的async/await无济于事。返回所有列表，但只有一个元素没有问题。

const axios = require('axios');
const {
    GraphQLObjectType,
    GraphQLInt,
    GraphQLString,
    GraphQLList,
    GraphQLSchema
    } = require('graphql');

// Country basic info
const CountryInfo = new GraphQLObjectType({
    name: "CountryInfo",
    fields: () => ({
        name: { type: GraphQLString },
        capital: { type: GraphQLString },
        population: { type: GraphQLInt },
        flag: { type: GraphQLString },
    })
})

// Root Query
const RootQuery = new GraphQLObjectType({
    name: 'RootQueryType',
    fields: {
        countryList: {
            type: new GraphQLList(CountryInfo),
            resolve(parent, args) {
                return axios.get('https://restcountries.eu/rest/v2/all').then( res => res.data );
            }
        },
        country: {
            type: CountryInfo,
            args: {
                name: { type: GraphQLString }
            },
            async resolve(parent, args) {
               const element = await axios.get(`https://restcountries.eu/rest/v2/name/${args.name}`).then(res => res.data);
               return element;
            }
        },
    },
});

module.exports = new GraphQLSchema({
    query: RootQuery,
});

Answer 1

如果您look at the response来自REST端点，则返回的是一系列国家/地区，而不仅仅是一个国家/地区对象。除非字段的类型为列表，否则您的解析器无法返回数组。同样，如果字段的类型为列表，则无法在解析器中返回对象。这应该起作用：

    country: {
        type: CountryInfo,
        args: {
            name: { type: GraphQLString }
        },
        async resolve(parent, args) {
           const elements = await axios.get(`https://restcountries.eu/rest/v2/name/${args.name}`).then(res => res.data);
           return elements[0];
        }
    },

GraphQL Javascript Axios返回null

1 个答案: