Extend Module

Extend a NPM module(s) by requiring and then merging with the given object(s).

Why?

Often I find myself writting code that does the same thing and writting the code elsewhere and then merging those common parts can save time on both development and maintenance.

Installation

Installation is simple:

$ npm i extend-module

Usage

In Sails you can define your base model as follows:

eg: api/base/models/Details.js base model

module.exports = {
  attributes: {
    name: {
        type: 'string',
    },
    age: {
         type: 'number',
    },
  },
}

An extending model can then use this package to extend the above base model as follows:

eg: api/models/Person.js model

const extend = require('extend-module');

module.exports = extend('../base/models/Details', {
  attributes: {
    name: {
        description: 'the name of the person',
        required: true,
    },
    sex: {
         type: 'string',
    },
  },
});

The resulting model will be as follows:

eg: resulting model

{
  attributes: {
    name: {
        type: 'string',
        description: 'the name of the person',
        required: true,
    },
    age: {
        type: 'number',
    },
    sex: {
         type: 'string',
    },
  },
}

Using the same method other models can inherit the same base attributes by extending the base details model.

Tips:

• You can use actual NPM packages to create your base models and use them in different apps:
  • ... extend('my-base-model', {...});
  • In that example my-base-model is a NPM package installed as a dependency using NPM ie: npm i my-base-model.
• You can specify multiple modules to require by passing an array of module names or paths:
  • ... extend(['my-base-model', 'my-other-base-model', ... ], {...});
  • Each module will extend the one before it in the order of left to right
  • The final module will be a merge of all the fiven modules
• You can specify multiple extending objects, all of them will extend the given module(s):
  • ... extend(['my-base-model', 'my-other-base-model', ... ], {...}, {...}, {...}, ... );
• To extend using only modules pass in an empty extending object:
  • ... extend(['my-base-model', 'my-other-base-model', ... ], {});
  • The modules will extend each other as usual, but the extending object will just be nothing.
  • It works the same if you pass just the first param ... extend(['my-base-model', 'my-other-base-model', ... ]);

Author

Emmanuel Mahuni. (c) 2018 MIT

Attributions

Andy Sutherland Sails Model Extension Example