Match the descriptions to these object contracts terms: Interface, Type alias, Optional property, Readonly property.

Object contractsConcept relationships

Choose a match for every item. Use each answer once.

A type alias names an existing type expression without creating a distinct runtime value.

Interfaces support declaration merging and describe required object members.

Readonly is enforced during type checking and does not itself create runtime immutability.

An optional property may be missing, so access generally requires handling undefined.