datamodel

Datamodel

Design datamodels with asynchronous functions and flows.

Contributors

• Nicolas Thouvenin

Installation

With npm do:

$ npm install datamodel

Tests

Use mocha to run the tests.

$ npm install mocha
$ mocha test

Examples

Example 1 : Create a object with 3 fields

var datamodel = require('datamodel');

datamodel()
.declare('field1', function(input, fill) {
    fill(input + ' hello');
})
.declare('field2', function(input, fill) {
    fill(input + ' world');
})
.append('field3', function(input, fill) {
    fill({ 'field1': this.field1, 'field2': this.field2});
})
.apply('->')
.then(function(res) {
    console.log('field1', res.field1);
    console.log('field2', res.field2);
    console.log('field3', res.field3);
})
.catch(function(err) {
    console.error('Error>', err.message);
});

output

field1 -> hello
field2 -> world
field3 { field1: '-> hello', field2: '-> world' }

Example 2 : Create a object with the content of 3 files

var fs = require('fs')
  , datamodel = require('datamodel');

datamodel()
.declare('dirname', function(input, fill) {
    fill('/etc');
})
.prepend('file1', function(input, fill) {
	fs.readFile(this.dirname + '/group', function (err, data) {
      fill(err ? err : data.toString().substring(0, 7).concat('...'));
	});
})
.append('file2', function(input, fill) {
	fs.readFile(this.dirname + '/hosts', function (err, data) {
      fill(err ? err : data.toString().substring(0, 7).concat('...'));
	});
})
.append('file3', function(input, fill) {
	fs.readFile(this.dirname + '/unknown', function (err, data) {
      fill(err ? err : data.toString().substring(0, 7).concat('...'));
	});
})
.apply()
.then(function(res) {
    console.log('Result>', res);
})
.catch(function(err) {
    console.error('Error>', err.message);
});

output

Error> ENOENT, open '/etc/unknown'

Example 3 : Declare a datamodel as package/module

obj.js

var datamodel = require('datamodel');

datamodel()
.declare('a', function(input, fill) {
    fill(input + 'A');
})
.append('b.1', function(input, fill) {
    fill(input + 'B1');
})
.append('b.2', function(input, fill) {
    fill(input + 'B1');
})
.append('b.3', function(input, fill) {
    fill(input + 'B3');
})
.complete('c', function(input, fill) {
    fill(input + 'C');
})
.attach(module);

index.js

var mdl = require('./obj.js');

mdl('#')
.then(function(o) {
	console.log('Result>', o);
})
.catch(console.error);

Output

Result>
{ a: '#A',
  'b.1': '#B1',
  'b.2': '#B1',
  'b.3': '#B3',
  c: '#C' }

Example 4 : Combine a datamodel and a route with Express

var app = require('express');

app.route('/resource/:param1/:param2').all(require('./obj.js'));

API Documentation

datamodel()

declare(String key, Function callback)

prepend(String key, Function callback)

append(String key, Function callback)

complete(String key, Function callback)

transform(Function callback)

You can only call transform once. So, if you need to apply two transforms, put them both in the same transform callback.

Example:

return datamodel()
.append('years', function(req, fill) {
  coll
  .aggregate(
    { $project: { Py: 1, _id: 0} },
    { $group: { _id: "$Py", occ: { $sum: 1} } })
  .then(fill)
  .catch(fill);
})
.transform(function(req, fill) {
  var n = this;
  var y = {};

  this.years.each(function (e) {
      y[e._id] = e.occ;
  });
  n.years = y;

  fill(n);
})

send(Function callback)

apply(Mixed input, Mixed output, Function callback) -> Promise

attach(Object module)

License

MIT/X11