Revision history [back]

The "any" type in TypeScript is used to represent any value, including values whose types are not known at compile-time or values that don't conform to a particular type's constraints. In the case of indexing, any type can be used to represent the index type because it is possible to index an object with a value of any type.

However, when using an expression of type "string" to index an object, TypeScript will raise a type error because it only allows properties to be accessed using keys that have been declared on the object's type. Since a "string" type expression may not necessarily be a valid key for the object, TypeScript will not allow it and will raise an error.