Variables can be filled in as parameter value, where the actual variable's value can be provided in code during instantiation.

This can be useful if your application for example accepts command line parameters that you want to pass to components at initialization time.

Types

JSON-LD Shortcut	URI	Description
Variable	oo:Variable	Resources of this @type are considered variables.

Example

For example, assuming a component ex:MyModule/MyComponent1 defines the following parameter:

{
  ...
  "@id": "ex:MyModule/MyComponent1",
  "parameters": [
    {
      "@id": "ex:MyModule/MyComponent1#param1"
    }
  ],
  ...
}

The following instantiation (i.e. config) can be defined:

{
  ...
  "@id": "http://example.org/MyInstance",
  "@type": "ex:MyModule/MyComponent1",
  "ex:MyModule/MyComponent1#param": {
    "@id": "urn:variables:myVariable",
    "@type": "Variable"
  }
}

Variable values can be set during instantiation using the variables option:

await loader.instantiateFromUrl('http://example.org/MyInstance', 'http://example.org/my/config.jsonld', undefined, {
  variables: {
    'urn:variables:myVariable': 'abc',
  },
});

This will lead to an instantiation of ex:MyModule/MyComponent1 with the following parameter mapping:

Parameter	Value
ex:MyModule/MyComponent#param	"abc"