# Interface Interfaces are capable of describing the wide range of shapes that JavaScript objects can take. It is one of TypeScript’s core principles for type checking. `interface` syntax is not supported in JavaScript. ## Required Properties Properties that does not have a question mark at the end of their names. When using the interface the property has to be assigned with the right type. ```ts interface LabeledValue { label: string; } ``` Example: ```js /** * @type {LabeledValue} */ const value = { label = 'test' }; ``` ## Optional Properties Properties that has a question mark (`?`) to the end of their names are marked as optional. Meaning the object _might_ have a property set. ```ts interface Options { type?: string[]; value: string; } ``` Example: ```js /** * @type {Options} */ const value = { value = 'required' }; ``` ## Learn More https://www.typescriptlang.org/docs/handbook/2/objects.html