mozy ·

A model library using lazy initialization, factories and instance registries.

Installation

npm install mozy

Defining models

import mozy from 'mozy';

export class Rect extends mozy.Model {

  get x() {
    return this.get('x');
  }
  set x(value) {
    this.set('x', value);
  }

  /**
   * Skipping y, width, height ...
   */

  _getDefaults() {
    return Object.assign(super._getDefaults(), {
      identity: Rect.identity,
      x: 0.0,
      y: 0.0,
      width: 0.0,
      height: 0.0
    });
  }

}

Rect.identity = 'shape.Rect';

/**
 * Skipping EdgeSizes definition
 */

export class Dimensions extends mozy.Model {

  get contentBox() {
    return this._getModel('contentBox');
  }

  get padding() {
    return this._getModel('padding');
  }

  get borderWidth() {
    return this._getModel('borderWidth');
  }

  get margin() {
    return this._getModel('margin');
  }

  _getModel(property) {
    return mozy.modelRegistry.getModel(this.get(property));
  }

  _getDefaults() {
    return Object.assign(super._getDefaults(), {
      identity: Dimensions.identity,
      contentBox: {identity: Rect.identity},
      padding: {identity: EdgeSizes.identity},
      borderWidth: {identity: EdgeSizes.identity},
      margin: {identity: EdgeSizes.identity}
    });
  }

}

Dimensions.identity = 'layout.Dimensions';

/**
 * Register identities
 */
mozy.modelIdentities.set(Rect.identity,       Rect);
mozy.modelIdentities.set(EdgeSizes.identity,  EdgeSizes);
mozy.modelIdentities.set(Dimensions.identity, Dimensions);

Using models

const dim = new Dimensions();
dim.contentBox.width = 100;
dim.contentBox.height = 40;
dim.padding.left = 10;
dim.padding.right = 10;
dim.borderWidth.top = 1;
dim.borderWidth.bottom = 1;

const jsonStr = JSON.stringify(dim);
console.log(jsonStr);

Will log:

{
  "identity": "layout.Dimensions",
  "uuid": "7366c996-1f8a-482b-ae36-c8e8b988c75c",
  "contentBox": {
    "identity": "shape.Rect",
    "uuid": "451775cc-3b44-4a3a-b9b3-e7ce110ddf80",
    "x": 0,
    "y": 0,
    "width": 100,
    "height": 40
  },
  "padding": {
    "identity": "layout.EdgeSizes",
    "uuid": "8c128fbb-c7b9-4fba-9cb5-005e5586554b",
    "top": 0,
    "right": 10,
    "bottom": 0,
    "left": 10
  },
  "borderWidth": {
    "identity": "layout.EdgeSizes",
    "uuid": "63a3c87c-9575-4a15-8084-2ba54bd13d38",
    "top": 1,
    "right": 0,
    "bottom": 1,
    "left": 0
  },
  "margin": {
    "identity": "layout.EdgeSizes",
    "uuid": "91ec1d41-3f06-4cf6-8c73-dbd6c8923cab",
    "top": 0,
    "right": 0,
    "bottom": 0,
    "left": 0
  }
}

Restoring the model from data dict:

const data = JSON.parse(jsonStr);
const dim = new Dimensions(data);
console.log(dim.padding.right) // 10

Or, if root constructor is unknown, using the registry:

const data = JSON.parse(jsonStr);
const model = mozy.modelRegistry.getModel(data);
console.log(model.padding.right) // 10

Listening to changes

Models extend EventEmitter, so you can subscribe to property-specific events or the generic change event:

const rect = new Rect();

rect.addEventListener('change width', (eventType, sender, newValue, oldValue) => {
  console.log(`Width changed from ${oldValue} to ${newValue}`);
});

rect.addEventListener('change', () => {
  console.log('Any property changed');
});

rect.toggle('selected');      // Convenience helper for booleans
rect.unset('height');         // Removes the property entirely
rect.resetData({ width: 10 }); // Resets while preserving identity/uuid
rect.dispose();               // Removes listeners and references

Advanced registry usage

Registries support custom key extractors, override policies, and multitons:

import mozy from 'mozy';

const registry = new mozy.Registry(mozy.modelFactory, {
  keyAttr: data => `custom-${data.uuid}`,
  keyValidator: key => key.startsWith('custom-'),
  allowOverrides: mozy.ALLOW_OVERRIDES
});

const rect = new Rect();
registry.register(rect);

// Shared registries without manual plumbing
const shared = mozy.Registry.get('shared-rects', mozy.modelFactory);
shared.register(rect);

Registry.get(name, factory) returns the same registry per name, making it easy to share caches or singletons between modules.

Test

npm test

The test script runs the Mocha suite through Babel and reports coverage via V8's built-in instrumentation (c8), emitting both text and lcov output. The suite targets >90% line coverage, including edge cases around the Registry and Factory helpers.

Build

Compiled artifacts now live in dist/:

• npm run build cleans the folder and emits both CommonJS (dist/cjs) and ESM (dist/esm) bundles via Babel.
• npm run watch rebuilds the CommonJS bundle on change for local development.
• Type declarations are generated via npm run build:types (also part of npm run build) and published under dist/types.
• Source maps are emitted inline for both bundles to simplify downstream debugging.

The package exports map points Node's import consumers at dist/esm/index.js and require callers at dist/cjs/index.js, so publishing only requires npm publish (the prepare script runs the build automatically).

For local releases, run npm run release to execute lint, tests (with coverage), and the full build in a single command before publishing.

TypeScript

First-party typings live under dist/types/index.d.ts and are generated from the hand-authored types/ source via npm run build:types. Consumers can rely on the types field in package.json without installing community-maintained definitions.

Changelog

Unreleased

Empty

0.6.3 – 2025-11-18

• Forced all direct and transitive consumers onto glob@^11.1.0 through npm overrides and pinned test-exclude to the last compatible glob@7 branch so coverage tasks keep running on Node 22.
• Regenerated the lockfile after running npm audit fix to ensure the patched dependency graph still passes npm run build and npm test.

0.6.2 – 2025-11-15

• Patched the js-yaml advisory by adding an explicit ^4.1.1 dependency and trimming the duplicate vulnerable copies that npm hoisted into the lockfile.

0.6.1 – 2025-11-14

• Expanded the published TypeScript declarations: Model now exposes its protected helpers, backing data references, and flags, and the exported identity map is renamed to modelIdentities for consistency.

0.6.0 – 2025-11-13

• Replaced wolfy87-eventemitter, lodash.clonedeep, and lodash.isplainobject with maintained or native alternatives to shrink the runtime surface.
• Upgraded to uuid@13 and now rely on its built-in helpers for UUID generation and validation.
• Added TypeScript declaration output, CI + coverage automation, and broadened Factory/Registry tests to maintain >90% line coverage.
• Dropped all @ts-nocheck directives and annotated Model, Factory, Registry, and the entrypoint with full JSDoc types so editors catch missing uuid/identity fields and event signatures out of the box.
• Hoisted UUID regexes, removed Object.keys().forEach allocations in default handling, cached structuredClone, and memoized registry key getters to shave allocations off hot paths like Model.copy() and Registry.getModel().
• Simplified distribution to ESM-only output (with first-party types) and inlined the tiny es6-error helper to keep install size minimal for internal consumers.
• Skipped redundant change events and reused registry keys; local Node 22 microbenchmarks show getModel (~100k ops) in ~0.70s, toggle (~100k ops) in ~0.03s, and resetData (~10k ops) in ~0.007s.

0.5.0

• Renamed getModelData to getDeepClonedModelData for clarity.
• Replaced usage of (previous) getModelData with getDataReference some places where deep cloning was unnecessary.
• Added assigning of previous data in Model.assignData (issue #6).
• Dependency updates.

0.4.0

• Bugfix for Issue #2: “Bug: copy replaces identical ...”
• Removed flag to preserve uuids in Model.copy.
• Fixed tests for Model.copy.
• Dev dependency updates.
• Lint fixes.

0.3.0

• Issue #2: “Bug: copy replaces identical uuids with different uuids, destroying internal references”
• Flag to preserve uuids in Model.copy.
• Tests for Model.copy.
• Dev env config and dependency updates (eslint, babel, nyc).

0.2.2

• Factory test fixes.
• toJSON method for model.

0.2.0

• Switched indentation from 4 spaces to 2.
• Merged ModelRegistry and Registry into Registry.
• Model:
  • Rewrite (simplified).
  • Now extends npm:wolfy87-eventemitter instead of npm:events.
• Factory:
  • Removed dependencies.
• Tests
  • More tests.
  • Replaced istanbul coverage with nyc.

License

This software is licensed under the MIT License.