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 datamodel with 3 files and 1 directory

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(function(err, res) {
    console.error('Error>', err);
    console.log('Result>', res);
});

output

Error> { [Error: Some fields are errors.] fields: [ 'file3' ] }
Result> { dirname: '/etc',
  file1: 'root:x:...',
  file2: '127.0.0...',
  file3: { [Error: ENOENT, open '/etc/unknown'] errno: 34, code: 'ENOENT', path: '/etc/unknown' } }

Example 2 : 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 util = require('util');

require('./obj.js')('#', function(o) {
    console.log(util.inspect(o, { colors:true, depth: null }));
  }
);

Output

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

Example 3 : 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)

attach(Object module)

License

MIT/X11