pinf-loader-js

Optimized JavaScript Bundle Loader ==================================

npm install pinf-loader-js
32 downloads in the last week
126 downloads in the last month

Optimized JavaScript Bundle Loader

Status: BETA Build Status

The PINF JavaScript Loader is an optimized (intended for production use) CommonJS package mappings based JavaScript module loader for the browser in only 1726 bytes (minified and zipped).

Online Demo: pinf.github.io/pinf-loader-js/workspace/www

Examples: github.com/pinf-it/pinf-it-bundler/tree/master/examples

What

The PINF JavaScript Loader provides a minimal CommonJS environment that requests optimized static JavaScript code files called Bundles from a server via GET requests and boots these into sandboxes in the browser identified by the requested URL.

Supported Environments:

Supported features:

  • Load bundled JavaScript programs from static URLs
  • Asynchronously load more program code bundles as needed
  • Load bundles cross-domain
  • Isolated module scopes
  • Isolated package namespaces
  • Isolated sandbox namespaces
  • Nested and circular dependency trees
  • Consistent mapping of static application resource URLs to loader namespaces
  • CommonJS/Modues/1.1
    • function(require, exports, module) {}
    • var ModuleAPI = require("./Module")
  • CommonJS/Packages/Mappings/C (proposal)
    • package.json ~ {mappings:{"PackageAlias": "PackageIdentifier"}}
    • var ModuleAPI = require("PackageAlias/Module")
  • CommonJS/Modues/2.0draft8 (draft)
    • global.require.memoize("PackageIdentifier/ModuleIdentifier", ModuleInitializer) (no dependency argument)
    • require.id(ModuleIdentifierString) (returns PackageIdentifier/ModuleIdentifier)
  • (Un)CommonJS(kriskowal)/Modules
    • require.async(ModuleIdentifierString, function loaded(ModuleAPI) {}, function error(e) {})
  • Proposed:
    • [global.]require.sandbox(SandboxURI, SandboxOptions, function loaded(sandbox) {}, function error(e) {})
    • [global.]require.sandbox.id to hold SandboxURI
    • sandbox.main()
    • require.bundle("BundleIdentifier", function ConsistentModuleSet(require) {})

Bundlers

Applications may be coded directly in the bundle format. Alternatively the bundle format may be treated as a compile target (typical). The following tools can generate PINF JavaScript Loader compatible bundles:

Why

Namespace isolation is essential for modular development when integrating arbitrary JavaScript libraries.

To achieve namespace isolation you need JavaScript libraries written in conventions that:

  • do not pollute the global namespace and
  • expose the library's API consistently

There are two evolving standards that specify such conventions:

When coding using these standards you need to keep in mind the two primary environments that the application will run in:

1) Development - Needs a loader that will, on demand, locate in the source tree, assemble and transport module source files to the browser for rapid development.

2) Production - Needs a build step that collects modules from the source tree and generates static optimized bundles that will be fetched by a loader optimized for production runtime performance.

The PINF JavaScript Loader is intended to run your application in development and production and may be fed by various Bundlers (see above).

Usage

http://localhost/index.html

<script type="text/javascript" src="loader.js"></script>
<script type="text/javascript">
    PINF.sandbox("app.js", function(sandbox) {
        sandbox.main();
    });
</script>

http://localhost/app.js

PINF.bundle("", function(require) {
    require.memoize("/main.js", function(require, exports, module) {
        exports.main = function(options) {
            console.log("HelloWorld!");
        }
    });
});

Examples

There are various feature examples that double as tests in ./features.

For an online demo of the loader features see pinf.github.io/pinf-loader-js/workspace/www.

For end-user examples of common use-cases see github.com/pinf-it/pinf-it-bundler/tree/master/examples.

Tips

  • When testing an application use the ./loader.js file to get all error messages.
  • When deploying an application us the ./loader.min.gz file for optimum performance.
  • When using a different loader during development make sure only supported API features of this loader are used. Load extra features along with your application by augmenting a sandbox.
  • When writing or generating bundles make sure one consistent set of statically linked modules is contained in each bundle file. Dynamic links to other modules or bundles must be made via require.async() or require.sandbox() respectively. The hierarchy of how your application nests these dynamic links will determine which modules must be included in subsequently loaded bundles to avoid sending the same modules twice.
  • A module can only be memoized once for each Canonical Identifier (comprising of SandboxIdentifier/PackageIdentifier/ModuleIdentifier). When placing modules into bundles make sure bundle filenames do not overlap with module filenames (and the reverse) as these have the potential to conflict (modules and bundles share the same logical file hierarchy). The idea is that a set of statically linked modules can always be combined into one file which is placed into the file that first requires the dependencies and represents the entry point into the bundle.

FAQ

Why does the loader not support feature X?

This loader is pretty much complete in terms of what needs to be implemented at the core loader level. Convenience features can be loaded along with the application by augmenting a sandbox.

Why does the loader not support AMD-style Loader Plugins?

Because loader plugins that are invoked by modifying the string literal passed to require() are not necessary and combine two concepts that should really be separate and implemented differently.

The AMD-style Loader Plugins can be replaced by:

  • Augmenting a sandbox
  • Loading helper modules within the application.
  • Using a loader that can run package-declared plugins.
  • Using a server helper to run plugins as modules are requested.

NOTE: Modules using some of the RequireJS loader plugins can be automatically converted to run on this loader using github.com/pinf-it/pinf-it-bundler.

How does the loader compare to almond?

While the RequireJS + almond combination focuses on loading of optimized AMD formatted modules this loader focuses on loading of optimized CJS formatted modules.

The AMD Specification is a small subset combining several CommonJS Concepts in a different form.

CommonJS represents a more pure and modular approach to devising arbitrary JavaScript application architectures by carefully layering a few core concepts into a framework that provides one small existential foundation for all other concepts. It allows for isolated namespaces, nested package dependency structures and runtime sandboxes as well as automatic conversion from source trees to optimized bundles. This loader is one existential foundation implementation and fully compatible with the CommonJS Concepts.

In contrast RequireJS + almond focuses on optimally loading (primarily into the browser) a list of packages containing JavaScript modules and resource files into a single namespace. In optimized form (for almond), several key RequireJS features are not supported.

Links

Influential Specifications:

Prior Art:

Test & Development

Requirements:

Run tests:

make test

Launch development workspace:

make run-dev
open http://localhost:8080/

Build

When running the development workspace the following files are automatically generated every time ./loader.js changes.

  • ./loader.min.js
  • ./loader.min.js.gz
  • ./loader.stripped.js
  • ./workspace/www/loader.min.js-size
  • ./workspace/www/loader.min.js.gz-size
  • ./workspace/www/loader.stripped.js.md5

You can also build these from the command-line:

make build
npm loves you