Keyable

Only the following types can be used as a key in a map or on an entity.

• Null
• Asset
• Boolean
• Category
• Color
• Enity
• Flag
• Keycode
• Numbers: including integers 123, negative numbers -123 and floating point numbers 0.5
• Vectors: including integer vectors @(12, 34) and floating point vectors @(0.5, 0.5)
• String
• Symbol

If Undefined is used as a key, it will be treated as null