Troubleshooting Handbook: Utilities

these are all built in, see source in es5.d.ts:

• ConstructorParameters: a tuple of class constructor's parameter types
• Exclude: exclude a type from another type
• Extract: select a subtype that is assignable to another type
• InstanceType: the instance type you get from a newing a class constructor
• NonNullable: exclude null and undefined from a type
• Parameters: a tuple of a function's parameter types
• Partial: Make all properties in an object optional
• Readonly: Make all properties in an object readonly
• ReadonlyArray: Make an immutable array of the given type
• Pick: A subtype of an object type with a subset of its keys
• Record: A map from a key type to a value type
• Required: Make all properties in an object required
• ReturnType A function's return type

This section needs writing, but you can probably find a good starting point with Wes Bos' ESLint config (which comes with a YouTube intro).