The most important class that is exposed by Components.js is the ComponentsManager, which essentially does only two things:

  1. It accepts module and component registrations, so that Components.js knows how to instantiate components.
  2. It instantiates components based on configurations.

There are however different ways to register modules and their components, and different ways to instantiate these components from configurations.

This is an example of registering and instantiating by URL:

const ComponentsManager = require('ComponentsManager').Loader;

// Create a manager
const manager = await{
  mainModulePath: __dirname, // Path to your npm package's root
  // Register our module
  moduleLoader: (registry) => registry.registerModule('path/or/url/to/my-module.jsonld'),

// Register our config
await manager.configRegistry.register('path/or/url/to/config-my-component.jsonld');

// Instantiate our config
const myInstance = await manager.instantiate('');

Example Source


ComponentsManager has a strict registration and instantiation phase. This means that all registrations should happen before instantiations. Any registrations being done after an instantiation has happened will result in a runtime exception.

This is needed because the ComponentsManager creates internal caches when the first instantiation is done to increase the efficiency of all following instantiations.

ComponentsManager Options

The ComponentsManager can be built with an optional options hash. This hash accepts the following optional entries:

Key Value Default
mainModulePath Path that should be considered the root Node module. Everything will happen relative to this path.
moduleLoader Callback for registering components and modules. Registration of all discoverable modules.
configLoader Callback for registering configurations.
constructionStrategy A strategy for constructing instances. ConstructionStrategyCommonJs
dumpErrorState If the error state should be dumped into componentsjs-error-state.json after failed instantiations. true
logLevel The logging level. warn
moduleState The module state. A newly created instances on the mainModulePath.
skipContextValidation If JSON-LD context validation should be skipped. true
typeChecking If values for parameters should be type-checked. true