model-store

Node js library allowing easy management of data stores respecting predefined models.

model-graph lets you build smart features on top of your request functions :

• update desired store with returned entity
• update any other linked stores if this entity has any linking attribute
• saved calls allow you to
  • keep trace of their last usage
  • synchronise 2 simultaneous same call with the same promise (instead of executing twice)
  • use one shot calls (unique instance over the entire program run)
• autogetters looks for a given entity id before executing request
• quick inserts update stores with your freshly created entity before running the request. Request return result updates this temporary entity, or deletes it on failure.
• models can be given a prototype to extend all of their entities features
• entity groups lets you organize entities in groups

Installation

npm --save i model-graph

API

DataScheme

import { DataScheme } from 'model-graph'; Lets you define models and links.

new DataScheme(models: obj?, opts: obj?)

models may contain model names and their options (key / value) opts may contain various DataScheme options.

DataScheme options :

• idAttribute : id attribute name, 'id' by default

void define(modelName: string, opts: obj?)

Creates a new Model identified by modelName, with opts options. This is the same method called by constructor with each key / value pairs. Note that modelName will also be the name of the corresponding DataStore.

Model options :

• idAttribute : id attribute name, if different from DataScheme level
• proto : prototype object to be inherited by modelName entities

void linking(schemeFn: function)

Call schemeFn with an object containing every models as parameter, in order to link them in a more convenient way.

object allStores()

Returns every stores in a single object

DataStore store(name: string)

Returns name store

Model model(name: string)

Returns name model

ModelRequest request(name: string)

Prepares and returns a new request on name stores

object savedCall(callId: string)

Returns informations about callId saved call, or undefined if it does not exist yet.

bool isRunningCall(callId: string)

Returns if callId is currently running or not.

Model

Template of a specific entity type, contains the few logic needed by datascheme declaration, should not be used outside this context.

Model should never be instantiated directly but only via DataScheme (constructor or define method), since it needs the enclosing DataScheme instance.

curInstance link(attrName: string?, linkedModel: Model, opts: obj?)

Links this model to linkedModel through attrName attribute. If attrName is meant to be an array (containing every linked entities), linkedModel should be an array as well (only containing the proper Model).

When receiving an entity of such a linked model, model-graph tries to extract the linked entity from attrName to its owner DataStore, leaving only ids in attrName.

Example : datascheme.model('todos').link('owner', datascheme.model('users'))

__link options : __

• via : object defining an autolink between the two models.
  • attr : indicates the remote model attribute name supposed to refer to an instance of current model.

With an autolink attribute, each linkedModel entity creation makes model-graph check if any entity of current model (referred by remote entity via.attr attribute) could have its attrName updated.

In short, this feature ensures that any incoming new entity would bind to their linked entities in a bidirectionnal way.

Example : datascheme.model('users').link('todos', [datascheme.model('todos')], { via: { attr: 'owner' } })

Suppose we already have an user 5 (with an empty todos attr) and we receive {objectId: 37, owner: 5, descr: "My awesome todo"} : the autolink would have user 5 todos attribute updated with [37] value

DataStore

Contains every entities of a specific model. Should never be instantiated directly, since DataScheme already takes care of this in the same time a Model is defined.

array getArray()

Returns an array of every entities

obj get(id: string)

Return entity corresponding to id

array getGroup(group: string)

Returns an array of group entities

array|object update(entities: array|object, opts?)

Update this store with entities (can be a single entity or an array) Always ensure that each entity still have its prototype. Returns entities, but please not it may have been re-instantiated / altered (prototypes).

update options :

• groups : array of groups entities should be assigned at

void delete(id: string)

Delete entity id and clear groups accordingly

void deleteFromGrp(id: string, group: string)

Remove id entity from group

object replace(oldId: string, newEntity: object, opts?)

Replace oldId entity by newEntity. Essentially, means we insert newEntity at same position than oldId.

ModelRequest

Interface between your request functions and datascheme, implements an important part of model-graph features. Built in a functionnal way such that most use cases will fit in one chained instruction (so every methods return current instance) Note that every intermediates values and calls are always promised, so think about it when using it. Requests have an attribute updatedStores (Set container) that lets you know which stores have been updated at any time, by store or delete methods.

Redux users should use the available middleware instead of directly ModelRequest.

construction

exported requestBuilder is a currying function that thake care of building the request with proper environment : datascheme object then desired store name.

import { requestBuilder } from 'model-graph';
// ... datascheme building
const schemeRequest = requestBuilder(datascheme);
const storeRequest = schemeRequest('users');
var myRequest = storeRequest().call(...)...

It is generally easier to build this from the datascheme : var myRequest = datascheme.request('users').call(...)...

currentInstance get(id: string)

Get and save entity id (via DataStore.get)

currentInstance value(value: any)

Save value

currentInstance then(fn)

Shortcut of currentInstance.result.then, currentInstance.result being the current promise

currentInstance store(opts?)

Generally the last method called in the chain, updates the target store with the last computed value, and save the store's returned value (e.g prototype update)

This is where various link extractions are operated.

store options :

• value : any value to overwrite current one
• groups : an array of groups to be given to DataStore.update
• replace : entity id to replace instead of update

Updates updatedStores.

currentInstance call(fn: function, ...args)

As soon as current promise has resolved, call fn with current promise result as first parameter, before args additional parameters.

Example :

function likeThisUser(user) {
    return ({id: user.id, likes: [...user.likes, 0]})
}
datascheme.request('users')
    .get(5)
    .call(likeThisUser)
    .store()
    .then(updated => {
        console.log(updated.likes)
    })

currentInstance savedCall(params: object)

Same as call, except that we are saving this call with a given id. Notifies DataScheme after both request beginning and ending (running true than false).

params:

• fn : required, the function to be executed
• callId : required, string identifying this call
• oneshot : true by default, prevents any other call callId execution, for the entire program running. If false, just prevent from 2 parallel executions.
• params : Array of parameters to be given to fn, empty by default

currentInstance delete(id: string?)

If id is undefined, looks for it in result.id (where result is last computed value). Then dispatch this deletion to DataStore.delete.

Updates updatedStores