Type Product is adding @id instead of identification

[JohJohan]

When generating Product with an id it will generate a @id instead of identification. https://schema.org/Product shows https://schema.org/identifier

This was probably introduced by #102

[Gummibeer]

The identifier property and its sub-properties are primarily useful in cases where the content is expressed as a textual string. Increasingly there are canonical URL/URI representations for each of these. All schema.org syntaxes already have built-in representation for URIs and URLs, e.g. in Microdata 'itemid', in RDFa 1.1, 'resource', in JSON-LD, '@id'. Generally it is preferable to use these unless there is a specific requirement to explicitly state the kind of identifier, or to provide additional / alternative identifiers (e.g., DOIs). Such requirements are common e.g. for scientific dataset description.
-- https://schema.org/docs/datamodel.html#identifierBg

After reading it again I think that a middle solution would be right.
@id is the correct key for simple string identifiers but typed identifiers should remain identifier.
I won't work on this until mid January. But I would welcome a PR that fixes this.

I wish you a merry Christmas! ⛄🎄🦌

[JohJohan]

Okay i would like to pick this up. I have an idea to create a interface class TypedIdentifierInterface that way i can check if i need to add @id or identifier is that a okay solution? And is there a way for me to find out what are simple string identifiers and what are tped identifiers?

[Gummibeer]

Hey,
we already have everything - only the snippet that replaces the identifier with @id has to be conditional.

schema-org/generator/templates/static/BaseType.php

Lines 129 to 135 in 3b22822

	protected function serializeIdentifier()
	{
	if (isset($this['identifier'])) {
	$this->setProperty('@id', $this['identifier']);
	unset($this['identifier']);
	}
	}

It should check if $this['identifier'] is a string or an object - you could check for Type interface.
Following the schema.org docs you can use an URL (which is string) or text or an instance of PropertyValue which we already have as an available type.
https://github.com/spatie/schema-org/blob/master/src/PropertyValue.php

[JohJohan]

Hello @Gummibeer,

Thank you for helping out. I managed to make a pull request #157.

Let me know if i missed something.