CouchRelay
CouchDB Object Document Model
- Support GraphQL Relay style cursor connection
- Built-in DataLoader
Model
Definition
A model corresponds to a database in CouchDB.
import { Model, field } from 'couchrelay';
class Post extends Model {
@field() title: string;
@field() content: string;
@field() authorId: string;
}Model.init() method ensures its corresponding database exists in CouchDB server
by creating a new db if it does not exists.
await Post.init();Then we get post database.
CouchRelay generates database name from Model's class name, like: Post -> post, MyUser -> my-user.
You can also specify its database name by giving static db property to model class.
class Post extends Model {
static db = 'my-post-db';
@field() title: string;
@field() content: string;
@field() authorId: string;
}Basic CRUD
const post = new Post();
post.title = 'My first post';
post.content = 'Boom!';
post.authorId = 'hanpama';
await post.$save();
console.log(post._id); // prints generated id
console.log(post._rev); // 1-......
Or you can do equivalent task like below:
const post = await Post.insert({
title: 'My first post',
content: 'Boom!',
authorId: 'hanpama',
});
console.log(post._id);You can update the document by modifying the object and saving it.
// Update
post.title = 'I am changing post title';
await post.$save();
console.log(post._rev); // 2-......You can also delete a document by calling $delete();
await post.$delete();Index
class Post extends Model {
@field() title: string;
@field() content: string;
@field() category: string;
@field() createdAt: number;
}
const postByCreatedAt = new Index(Post, {
ddoc: 'post-by-created-at',
name: 'index',
index: {
fields: ['createdAt', '_id'],
},
} ,{
maxCount: 10,
});await postByCreatedAt.init()Quering with index
const res = await postByCreatedAt.query({ selectors: [{ title: 'Something' }] });Quering with index connection
You can execute query with GraphQL relay connection arguments using getConnection().
Its returning object has format of relay connection.
const connection = await postByCreatedAt.getConnection().exec({ first: 5 });
console.log(connection.pageInfo);
console.log(connection.edges);
console.log(connection.edges[0].cursor);
console.log(connection.edges[0].node);View
class Post extends Model {
@field() title: string;
@field() content: string;
@field() category: string;
@field() createdAt: number;
}
const postByCreatedAt = new View(Post, 'post-by-created-at', {
limit: 10,
map: `
function(doc) {
emit([doc.createdAt, doc._id], null);
}
`
});await postByCreatedAt.init();Querying with view
You can query values and documents with view instance.
await postByCreatedAt.getDoc(key);
await postByCreatedAt.getManyDocs(keys);
// it is not useful here because all the values are null
await postByCreatedAt.getValue(key);
await postByCreatedAt.getManyValues(keys)Quering with view connection
const connection = await postByCreatedAt.getDocConnection().exec({ last: 5 });
console.log(connection.pageInfo);
console.log(connection.edges);
console.log(connection.edges[0].cursor);
console.log(connection.edges[0].node);allDocs view
A Model class has allDocs view by default.
const post = await Post.allDocs().getDoc('00003bbd26096c0bb063eb0797d71a7');You can query allDocs() view in the same way where you query on any other views.
