我有这种形式的架构
type User{
id: String!
name: String
posts: [Post]
}
type Post {
id: String!
userId: String
body: String
}
使用facebook dataloader批量处理请求
query {
GetAllUser {
id
name
posts {
id
body
}
这是我已经做过的
const GetPost = async function (root, params, context, info) {
const userId = root.id;
const data = await loader.load(userId);
//console.log({userId, loader, data});
return data;
}
const loader = new DataLoader(userIds => {
return PostModel.find({ userId: { $in: userIds } }).then(posts => {
const postsById = keyBy(posts, "_id");
console.log({postsById, posts})
const a = userIds.map(post => postsById[post]);
//console.log({userIds, posts, postsById, a});
return a;
});
});
如果我使用const postsById = keyBy(posts, "_id");，它将返回[ undefined, undefined, undefined ] as a；如果我返回const postsById = keyBy(posts, "userId");，它将返回
[ { media: [],
reaction: [],
comment: [],
_id: 5bdef792bea4733c64bf5fee,
body: 'Today is sunday, we give God praise',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-04T13:43:46.253Z,
updatedAt: 2018-11-04T13:43:46.253Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdd949090d23c5aa430d575,
body: ' Ooop! going for a holiday soon',
privacy: 'public',
userId: 5bdd79ea0fef4004a040d110,
createdAt: 2018-11-03T12:29:04.385Z,
updatedAt: 2018-11-03T12:29:04.385Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdd8b5ea95dda4854c50d39,
body: 'i am a man',
privacy: 'public',
userId: 5bdd86dc1c76593b18a727db,
createdAt: 2018-11-03T11:49:50.244Z,
updatedAt: 2018-11-03T11:49:50.244Z,
__v: 0 } ]
为
但是console.log({posts})
posts:
[ { media: [],
reaction: [],
comment: [],
_id: 5bda0d61c255f33550813a86,
userId: 5bd4dfa30a00291820c7896d,
body: 'I am very Happy today',
privacy: 'everyone',
createdAt: 2018-10-31T20:15:29.717Z,
updatedAt: 2018-10-31T20:15:29.717Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bda0d74c255f33550813a87,
userId: 5bd4dfa30a00291820c7896d,
body: 'Thank God for today',
privacy: 'everyone',
createdAt: 2018-10-31T20:15:48.218Z,
updatedAt: 2018-10-31T20:15:48.218Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bda0d86c255f33550813a88,
userId: 5bd4dfa30a00291820c7896d,
body: 'Deeka my bro',
privacy: 'everyone',
createdAt: 2018-10-31T20:16:06.042Z,
updatedAt: 2018-10-31T20:16:06.042Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdc03c4fec5eb3a4cfe2a57,
body: 'What are you saying',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-02T07:59:00.860Z,
updatedAt: 2018-11-02T07:59:00.860Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdc03d5fec5eb3a4cfe2a58,
body: 'What are you saying',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-02T07:59:17.672Z,
updatedAt: 2018-11-02T07:59:17.672Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdc0493fec5eb3a4cfe2a59,
body: 'Today is Beautiful',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-02T08:02:27.585Z,
updatedAt: 2018-11-02T08:02:27.585Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdc0493fec5eb3a4cfe2a5a,
body: 'Today is Beautiful',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-02T08:02:27.590Z,
updatedAt: 2018-11-02T08:02:27.590Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdc0493fec5eb3a4cfe2a5b,
body: 'What do u know about love',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-02T08:02:27.590Z,
updatedAt: 2018-11-03T03:06:04.308Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdc0493fec5eb3a4cfe2a5c,
body: 'Love is wicked',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-02T08:02:27.617Z,
updatedAt: 2018-11-03T03:04:27.168Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdc0ac953b24320885bb19d,
body: 'Today is really Beautiful',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-02T08:28:57.931Z,
updatedAt: 2018-11-03T02:48:57.201Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdd8b5ea95dda4854c50d39,
body: 'i am a man',
privacy: 'public',
userId: 5bdd86dc1c76593b18a727db,
createdAt: 2018-11-03T11:49:50.244Z,
updatedAt: 2018-11-03T11:49:50.244Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdd8db4702a272b14e5e4d3,
body: ' Ooop! going for a holiday soon',
privacy: 'public',
userId: 5bdd79ea0fef4004a040d110,
createdAt: 2018-11-03T11:59:48.279Z,
updatedAt: 2018-11-03T11:59:48.279Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdd949090d23c5aa430d575,
body: ' Ooop! going for a holiday soon',
privacy: 'public',
userId: 5bdd79ea0fef4004a040d110,
createdAt: 2018-11-03T12:29:04.385Z,
updatedAt: 2018-11-03T12:29:04.385Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdef776bea4733c64bf5feb,
body: 'Today is sunday, we give God praise',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-04T13:43:18.777Z,
updatedAt: 2018-11-04T13:43:18.777Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdef776bea4733c64bf5fec,
body: 'Today is sunday, we give God praise',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-04T13:43:18.782Z,
updatedAt: 2018-11-04T13:43:18.782Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdef776bea4733c64bf5fed,
body: 'Today is sunday, we give God praise',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-04T13:43:18.784Z,
updatedAt: 2018-11-04T13:43:18.784Z,
__v: 0 },
{ media: [],
reaction: [],
comment: [],
_id: 5bdef792bea4733c64bf5fee,
body: 'Today is sunday, we give God praise',
privacy: 'public',
userId: 5bd4dfa30a00291820c7896d,
createdAt: 2018-11-04T13:43:46.253Z,
updatedAt: 2018-11-04T13:43:46.253Z,
__v: 0 } ] }
userIds包含此
userIds:
[ '5bd4dfa30a00291820c7896d',
'5bdd79ea0fef4004a040d110',
'5bdd86dc1c76593b18a727db' ],
您可以看到获得了所有帖子，但是要为每个用户返回没有数据加载器的帖子数组，它将使用以下代码工作
const GetPost = async function (root, params, context, info) {
const post = await PostModel.find({
userId: root.id
}).exec();
if (!post) {
throw new Error('Post not found');
}
console.log({post})
return post;
}
解析器为posts: GetPost
答案 0 :(得分：0)
代替此加载器功能
const loader = new DataLoader(userIds => {
return PostModel.find({ userId: { $in: userIds } }).then(posts => {
const postsById = keyBy(posts, "_id");
console.log({postsById, posts})
const a = userIds.map(post => postsById[post]);
//console.log({userIds, posts, postsById, a});
return a;
});
});
我用了这个
const loader = new DataLoader(userIds => {
return await PostModel.find({ userId: { $in: userIds } }).then(posts => {
const allPosts = groupBy(posts, 'userId');
return userIds.map(post => allPosts[post] || []);
});
});
使用loadash groupBy首先获得的结果将被格式化为
[[object, object, object], [object, object, object, object], [object]]