jsontableschema-orm-js

An (object relational) mapper based on JSON Table Schema descriptors.
This library created to be used together with the jsontableschema-js to simplify working with data.

Installation

npm install jsontableschema-models

Model

Represents the row of the data in the given table. It instantiated via define method, and returns Promise and inside resolved Promise model object is available, but this object should be loaded by the Storage (see below) to be able to work with it.

Config object:

• tableName - name of the collection
• resource - URL or path to the resource with data
• descriptor - JSON table schema descriptor
• instanceMethods - custom methods to work with data will be available on every instance of the model (see example below)

Methods:

There is only 1 method possible to use on model and inside instance methods:

• keyed - map of values to headers of the data row

Storage

Component which take care of loading data of the model into memory and keep it under the collection, which has same name as model table name. Available methods:

• add(tableName: string, items: any[]) - Add to collection. If collection does not exists, creates new.
• all(tableName: string) - Get all data from table. Returns model for each row
• load(model) - Load data of model into memory

Usage

1. First need to create model definition:

import jtsModels from 'path/to/lib'

const model = jtsModels.define({
  tableName: 'cases',
  resource: 'http://url/to/csv/file/with/data',
  descriptor: {
              "fields": [
                {
                  "name": "id",
                  "title": "",
                  "description": "",
                  "type": "integer",
                  "format": "default"
                },
                {
                  "name": "name",
                  "title": "",
                  "description": "",
                  "type": "string",
                  "format": "default"
                }
              ]
            },
  instanceMethods: {
    proceed: function() {
      const data = this.keyed()
      let type = 'odd'
      if(data.id % 2 === 0) {
        type = 'even'
      }
      return {
        type: type,
        name: data.name
      }
    }
  }
})

2. Load model by the storage:

model().then(model => {
  // load data of the model to memory
  jtsModels.Storage.load(model).then(() => {
    // get all data from table. Returns model for each row
    const models = jtm.Storage.all(model.tableName)
    const result = []
    // ... iterate through all the models in collection and do something with data
    models.forEach(model => {
      // call instance method from config of the model
      result.push(model.proceed());
    })
  }, error => {
    // error in case if storage can't load model
  });
}, error => {
  // do something in case error if model definition is broke
});