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    simpleddp
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    2.2.4 • Public • Published

    npm version Build Status Dependency Status devDependency Status

    SimpleDDP 🥚

    The aim of this library is to simplify the process of working with Meteor.js server over DDP protocol using external JS environments (like Node.js, Cordova, Ionic, ReactNative, etc).

    It is battle tested 🏰 in production and ready to use 🔨.

    If you like this project ⭐ is always welcome.

    Important

    SimpleDDP is written in ES6 and uses modern features like promises. Though its precompiled with Babel, your js environment must support ES6 features. So if you are planning to use SimpleDDP be sure that your js environment supports ES6 features or include polyfills yourself (like Babel Polyfill).

    Project uses semantic versioning 2.0.0.

    DDP (protocol) specification.

    CHANGE LOG

    Install

    npm install simpleddp --save

    Documentation

    Plugins

    Adding custom EJSON types

    Example

    First of all you need WebSocket implementation for your node app. We will use isomorphic-ws package for this since it works on the client and serverside.

    npm install isomorphic-ws ws --save

    Import/require simpleDDP.

    const simpleDDP = require("simpleddp"); // nodejs
    const ws = require("isomorphic-ws");

    or

    import simpleDDP from 'simpleDDP'; // ES6
    import ws from 'isomorphic-ws';

    Now you should make a new simpleDDP instance.

    let opts = {
        endpoint: "ws://someserver.com/websocket",
        SocketConstructor: ws,
        reconnectInterval: 5000
    };
    const server = new simpleDDP(opts);

    Connection is not going to be established immediately after you create a simpleDDP instance. If you need to check your connection simply use server.connected property which is true if you are connected to the server, otherwise it's false.

    You can also add some events for connection status.

    server.on('connected', () => {
        // do something
    });
     
    server.on('disconnected', () => {
        // for example show alert to user
    });
     
    server.on('error', (e) => {
        // global errors from server
    });

    As an alternative you can use a async/await style (or then(...)).

    (async ()=>{
      await server.connect();
      // connection is ready here
    })();

    The next thing we are going to do is subscribing to some publications.

    let userSub = server.subscribe("user_pub");
    let otherSub = server.subscribe("other_pub",'param1',2); // you can specify arguments for subscription
     
    (async ()=>{
      await userSub.ready();
      let nextSub = server.subscribe("next_pub"); // subscribing after userSub is ready
      await nextSub.ready();
      //all subs are ready here
    })();

    You can fetch all things you've subscribed for using server.collection method. Also you can get reactive data sources (plain js objects which will be automatically updated if something changes on the server).

    (async ()=>{
     
      // call some method
      await server.call('somemethod');
     
      let userSub = server.subscribe("user",userId);
      await userSub.ready();
     
      // get non-reactive user object
      let user = server.collection('users').filter(user=>user.id==userId).fetch()[0];
     
      // get reactive user object
      let userReactiveCursor = server.collection('users').filter(user=>user.id==userId).reactive().one();
      let userReactiveObject = userReactiveCursor.data();
     
      // observing the changes
      server.collection('users').filter(user=>user.id==userId).onChange(({prev,next})=>{
        console.log('previus user data',state.prev);
        console.log('next user data',state.next);
      });
     
      // observing changes in reactive data source
      userReactiveCursor.onChange((newData)=>{
        console.log('new user state', newData);
      });
     
      let participantsSub = server.subscribe("participants");
     
      await participantsSub.ready();
     
      let reactiveCollection = server.collection('participants').reactive();
     
      // reactive reduce
      let reducedReactive = reactiveCollection.reduce((acc,val,i,arr)=>{
        if (i<arr.length-1)  {
          return acc + val.age;
        } else {
          return (acc + val.age)/arr.length;
        }
      },0);
     
      // reactive mean age of all participants
      let meanAge = reducedReactive.data();
     
      // observing changes in reactive data source
      userReactiveCursor.onChange((newData)=>{
        console.log('new user state', newData);
      });
    })();

    Install

    npm i simpleddp

    DownloadsWeekly Downloads

    1,180

    Version

    2.2.4

    License

    MIT

    Unpacked Size

    93.5 kB

    Total Files

    26

    Last publish

    Collaborators

    • gregivy