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    Core.js EventTypes.js Kronicle.js Module.js ArrayDataSource.js Component.js Controller.js DataSource.js DataSources.js DataSourcesEvents.js View.js

  • DataSource.js

  • ¶ 
    import {Module} from '../Module.js';
import {events} from './DataSourcesEvents.js';
import {default as PubSub} from 'pubsub-js';
  • ¶

    Kronicle.DataSource class

    depends: Kronicle.Module, Kronicle.DataSourcesEvents, pubsub-js This class is used to implement a CRUD datasource for use in Kronicle. The constructor takes an args object which has the following properties:

    • source - a datasource implementation.
    • name - the name of the datasource.
    export class DataSource extends Module {
    constructor(args = {source: undefined, name: ''}) {
        let emptySource = {
            login: (user, pass, cb) => { cb(); return; },
            create: (item, cb) => { cb(); return; },
            update: (item, cb) => { cb(); return; },
            remove: (item, cb) => { cb(); return; },
            get: (item, cb) => { cb(); return; }
        };
        this.source = args.source || emptySource;
        super({name: args.name});
        return this;
    }
  • ¶

    login method

    This is impemented in the source if the datasource requires a login. The method takes three arguments

    • user - the username needed for login.
    • pass - the password needed for login.
    • cb - the callback to be called after login attempt, this is passed two arguments
      • err - if an error is caused by the login attemp.
      • data - a successful login data object, often the user or token used in an API An OnLogin event is triggered after the attempt, it’s passed the user and pass arguments.
        login(user, pass, cb) {
        this.source.login(user, pass, (err, data) => {
            this._doCbIfExists(cb, err, data);
            PubSub.publish(events.OnLogin, user, pass, events.OnLogin);
        });        
    }
  • ¶

    create method

    This method is implemented in the source to create a new source item. The method takes two arguments

    • item - the item to be created.
    • cb - the callback to be called after creation, this is passed two arguments
      • err - if an error is caused by the creation attempt.
      • data - a successfully created item. An OnCreate event is triggered after the attempt, it’s passed the item as an argument.
        create(item, cb) {
        this.source.create(item, (err, data) => {
            this._doCbIfExists(cb, err, data);
            PubSub.publish(events.OnCreate, item, events.OnCreate);
        });        
    }
  • ¶

    update method

    This method is implemented in the source to update a source item. The method takes two arguments

    • item - the item to be updaed.
    • cb - the callback to be called after the update, this is passed two arguments
      • err - if an error is caused by the update attempt.
      • data - a successfully updated item. An OnUpdate event is triggered after the attempt, it’s passed the item as an argument.
        update(item, cb) {
        this.source.update(item, (err, data) => {
            this._doCbIfExists(cb, err, data);
            PubSub.publish(events.OnUpdate, item, events.OnUpdate);
        });        
    }
  • ¶

    remove method

    This method is implemented in the source to remove a source item. The method takes two arguments

    • item - the item to be removed.
    • cb - the callback to be called after the removal, this is passed two arguments
      • err - if an error is caused by the removal attempt.
      • data - a successfully removed item. An OnRemove event is triggered after the attempt, it’s passed the item as an argument.
        remove(item, cb) {
        this.source.remove(item, (err, data)=> {
            this._doCbIfExists(cb, err, data);
            PubSub.publish(events.OnRemove, item, events.OnRemove);
        });        
    }
  • ¶

    get method

    This method is implemented in the source to get a source item. The method takes two arguments

    • item - the item to get.
    • cb - the callback to be called after attempting to get the item, this is passed two arguments
      • err - if an error is caused by the get attempt.
      • data - a successfully retrieved item. An OnGet event is triggered after the attempt, it’s passed the item as an argument.
        get(item, cb) {
        this.source.get(item, (err, data) => {
            this._doCbIfExists(cb, err, data);
            PubSub.publish(events.OnGet, item, events.OnGet);
        });
    }
  • ¶

    onLogin method

    This method is used as a hook into the OnLogin event. It is passed one argument:

    • cb - the callback to be called after a login attemp, it’s passed the following arguments.
      • user - the username of the attempt.
      • pass - the password of the attempt.
        onLogin(cb) {
         PubSub.subscribe(events.OnLogin, cb);
    }
  • ¶

    onCreate method

    This method is used as a hook into the OnCreate event. It is passed one argument:

    • cb - the callback to be called after a create attempt, it’s passed the following argument
      • item - the item that was attempted to be created.
        onCreate(cb) {
        PubSub.subscribe(events.OnCreate, cb);
    }
  • ¶

    onUpdate method

    This method is used as a hook into the OnUpdate event. It is passed one argument:

    • cb - the callback to be called after an update attempt, it’s passed the following argument
      • item - the item that was attempted to be updated.
        onUpdate(cb) {
        PubSub.subscribe(events.OnUpdate, cb);
    }
  • ¶

    onRemove method

    This method is used as a hook into the OnRemove event. It is passed one argument:

    • cb - the callback to be called after a removal attempt, it’s passed the following argument
      • item - the item that was attempted to be removed.
        onRemove(cb) {
        PubSub.subscribe(events.OnRemove, cb);
    }
  • ¶

    onGet method

    This method is used as a hook into the OnGet event. It is passed one argument:

    • cb - the callback to be called after a retrieval attempt, it’s passed the following argument
      • item - the item that was attempted to be retrieved.
        onGet(cb) {
        PubSub.subscribe(events.OnGet, cb);
    }
  • ¶

    _doCBIfExists

    This method is to be used internally and not meant to be used by consuming modules. This method checks if a callback exists and if so, calls it with err and data arguments passed to it. It take three arguments:

    • cb - the callback to check and call if exists.
    • err - an error to be passed to the callback if exists.
    • data - the data to be passed to the callback if exists.
        _doCbIfExists(cb, err, data) {
        if(cb){
            cb(err, data);
        }
    }
}