Is there a standard approach to specifying a property to be a dictionary or map keyed by string with a value type T specified somewhere else in the schema?

For example, suppose you want to model a user's favorite movies where the key type is the name of the movie and the value type is some set of attributes about the movie (year made, budget, gross income, etc.)

I imagine you could model first a MovieDataPair as a type with *name* property and a *value* property containing the desired attributes. Then the map would be an array of those. But, then you would need a special unique constraint that ensured any movie name only appeared once.

Is there something in json schema to support this, or a standard pattern used for it?
If not built in support in json schema, what about other schema solutions?