Exercise: default settings

Write a function function withDefaults(options) that returns a new settings object: it has every property of options, and the properties size and color that options lacks come from the default settings { size: "M", color: "black" }.

• withDefaults({ size: "L" }) → { size: "L", color: "black" }
• withDefaults({}) → { size: "M", color: "black" }
• withDefaults({ color: "red", logo: "cat" }) → { size: "M", color: "red", logo: "cat" }

Constraints: options is an object with string values, possibly empty; options itself does not change, and the result is a new object every time, even when options has both properties; the order of keys in the result does not matter.

Do not add extra imports unless the task says so explicitly.