如何正确使用 GraphQLList 和 GraphQLInterfaceType?
How do you use GraphQLList and GraphQLInterfaceType correctly?
我开始使用 GraphQL。我正在尝试将数据解析为 GraphQL 类型。我不明白为什么以下内容不起作用。
鉴于此数据:
{
"kind": "youtube#searchListResponse",
"etag": "\"CuSCwMPVmgi8taDtE2LV6HdgkN0/USvbH1nSht52L3y8EP6BIwVRhgM\"",
"items": [{
"kind": "youtube#searchResult",
"etag": "\"CuSCwMPVmgi8taDtE2LV6HdgkN0/xpywjUARlQ0Ai4IucTvXRNCfTcE\"",
"id": {
"kind": "youtube#video",
"videoId": "zvRbU1Ql5BQ"
}
}]
}
这是输入代码。
const ItemType = new GraphQLInterfaceType({
name: 'Item',
fields: {
kind: { type: StringType },
},
});
const YoutubeDataType = new GraphQLObjectType({
name: 'PublicYoutube',
fields: {
kind: { type: new GraphQLNonNull(StringType) },
etag: { type: new GraphQLNonNull(StringType) },
items: { type: new GraphQLList(ItemType) }, // returns null
// items: { type: StringType }, // returns "[object Object]"... so it's being passed in
},
});
这是通过 GraphiQL 返回的内容。为什么 items
等于 null
?
{
"data": {
"publicyoutube": {
"kind": "youtube#searchListResponse",
"etag": "\"CuSCwMPVmgi8taDtE2LV6HdgkN0/OspGzY61uG9sSD_AWlfwkTBjG-8\"",
"items": [
null
]
}
},
"errors": [
{
"message": "Cannot read property 'length' of undefined"
}
]
}
感谢您的帮助。
我误解了 GraphQLInterfaceType 的用途,使用了错误的方法。而不是使用 GraphQLInterfaceType,它应该是 GraphQLObjectType;
const ItemType = new GraphQLObjectType({
name: 'Item',
fields: {
kind: { type: StringType },
},
});
const YoutubeDataType = new GraphQLObjectType({
name: 'PublicYoutube',
fields: {
kind: { type: new GraphQLNonNull(StringType) },
etag: { type: new GraphQLNonNull(StringType) },
items: { type: new GraphQLList(ItemType) }, // returns null
// items: { type: StringType }, // returns "[object Object]"... so it's being passed in
},
});
输出:
{
"data": {
"publicyoutube": {
"kind": "youtube#searchListResponse",
"etag": "\"CuSCwMPVmgi8taDtE2LV6HdgkN0/-aZNXBVLYOJwPMdleXmbTlJSo_E\"",
"items": [
{
"kind": "youtube#searchResult"
}
]
}
}
}
我开始使用 GraphQL。我正在尝试将数据解析为 GraphQL 类型。我不明白为什么以下内容不起作用。
鉴于此数据:
{
"kind": "youtube#searchListResponse",
"etag": "\"CuSCwMPVmgi8taDtE2LV6HdgkN0/USvbH1nSht52L3y8EP6BIwVRhgM\"",
"items": [{
"kind": "youtube#searchResult",
"etag": "\"CuSCwMPVmgi8taDtE2LV6HdgkN0/xpywjUARlQ0Ai4IucTvXRNCfTcE\"",
"id": {
"kind": "youtube#video",
"videoId": "zvRbU1Ql5BQ"
}
}]
}
这是输入代码。
const ItemType = new GraphQLInterfaceType({
name: 'Item',
fields: {
kind: { type: StringType },
},
});
const YoutubeDataType = new GraphQLObjectType({
name: 'PublicYoutube',
fields: {
kind: { type: new GraphQLNonNull(StringType) },
etag: { type: new GraphQLNonNull(StringType) },
items: { type: new GraphQLList(ItemType) }, // returns null
// items: { type: StringType }, // returns "[object Object]"... so it's being passed in
},
});
这是通过 GraphiQL 返回的内容。为什么 items
等于 null
?
{
"data": {
"publicyoutube": {
"kind": "youtube#searchListResponse",
"etag": "\"CuSCwMPVmgi8taDtE2LV6HdgkN0/OspGzY61uG9sSD_AWlfwkTBjG-8\"",
"items": [
null
]
}
},
"errors": [
{
"message": "Cannot read property 'length' of undefined"
}
]
}
感谢您的帮助。
我误解了 GraphQLInterfaceType 的用途,使用了错误的方法。而不是使用 GraphQLInterfaceType,它应该是 GraphQLObjectType;
const ItemType = new GraphQLObjectType({
name: 'Item',
fields: {
kind: { type: StringType },
},
});
const YoutubeDataType = new GraphQLObjectType({
name: 'PublicYoutube',
fields: {
kind: { type: new GraphQLNonNull(StringType) },
etag: { type: new GraphQLNonNull(StringType) },
items: { type: new GraphQLList(ItemType) }, // returns null
// items: { type: StringType }, // returns "[object Object]"... so it's being passed in
},
});
输出:
{
"data": {
"publicyoutube": {
"kind": "youtube#searchListResponse",
"etag": "\"CuSCwMPVmgi8taDtE2LV6HdgkN0/-aZNXBVLYOJwPMdleXmbTlJSo_E\"",
"items": [
{
"kind": "youtube#searchResult"
}
]
}
}
}