Boot script for fragmented loading of Loopback models

!Fragmenting Loopback Models.md

Fragmenting Loopback Models

Hey! I've bundled this approach into a component: https://github.com/doublemarked/loopback-component-model-fragments

This boot script will load module components on app initialization. Stick this file in server/boot. Components are looked for in the directory common/models/model-name. The script will load recursively any script from that directory, passing it the Model handle as a parameter (just like model.js loads). Conveniently, since this is occuring during the boot phase, those model scripts will execute at a later phase than model.js, meaning PersistedModel is already initialized and all peer model handles are already usable. Note - it's necessary for you to still maintain a model.js file for Loopback to load the model at all.

AUTHOR: Heath Morrison | @govright.org | http://github.com/doublemarked

QUESTIONS? Write me or join us on Gitter: https://gitter.im/strongloop/loopback

boot-script.js

// AUTHOR: Heath Morrison | <firstname>@govright.org | http://github.com/doublemarked 
// QUESTIONS? Write me or join us on Gitter: https://gitter.im/strongloop/loopback
//
// This boot script will load module components on app initialization. Stick this file in server/boot. 
// Components are looked for in the directory common/models/model-name. The script will load recursively any
// script from that directory, passing it the Model handle as a parameter (just like model.js loads). 
// Conveniently, since this is occuring during the boot phase, those model scripts will execute at a later
// phase than model.js, meaning PersistedModel is already initialized and all peer model handles are already usable. 
// Note - it's necessary for you to still maintain a model.js file for Loopback to load the model at all.

module.exports = function(app) {
  Object.keys(app.models).forEach(function (key) {
    loadComponents(app.models[key]);
  });
};

function loadComponents(Model, options) {
  options = options || {};
  var componentsPath = options.path || Model.settings.components || 'common/models/' + slugify(Model.modelName);

  try {
    recursiveRequire(appRoot + '/' + componentsPath);
  } catch (e) {
    // anything other than 'file not found' should be a hard fail
    if (e.code !== 'ENOENT') {
      console.error('Failure loading component path:', appRoot + '/' + componentsPath);
      process.exit(1);
    }
  }

  function recursiveRequire(sourcePath) {
    fs.readdirSync(sourcePath).forEach(function (f) {
      var filePath = sourcePath + '/' + f;
      if (fs.lstatSync(filePath).isDirectory()) {
        recursiveRequire(filePath);
      } else if (path.extname(f) === '.js') {
        require(filePath)(Model);
      }
    });
  }
}

// Works for 99% of cases. For others, set explicit path via options/config.
function slugify(name) {
  name = name.replace(/^[A-Z]+/, function (s) { return s.toLowerCase(); });
  return name.replace(/[A-Z]/g, function (s) { return '-' + s.toLowerCase(); });
}

Example Directory Structure.md

Here's an example of how one of our models (Scope) has been broken into components:

common/models/scope
common/models/scope/hooks.js
common/models/scope/linker.js
common/models/scope/methods.js
common/models/scope/overrides.js
common/models/scope/remotes
common/models/scope/remotes/find-linked.js
common/models/scope/remotes/find-one-linked.js
common/models/scope/remotes/find-parent.js
common/models/scope/validations.js
common/models/scope.js
common/models/scope.json

If desired, you can also split up your static methods into a

    methods/

directory as well