How to do dynamic objects in TypeScript

Question

Is there any way to define a dynamic object type in TypeScript? In the following example, I would like to define a type for "My Complex Type" by saying:

Objects of type "My Complex Type" are objects having "any number of properties" but the values of those properties must be of type IValue.

// value interface interface IValue {     prop:string }  // My Complex Type myType = {     field1:IValue     field2:IValue     .     .     .     fieldN:IValue }  // Using My Complex Type   interface SomeType {     prop:My Complex Type } 

Answer 1

Yes, that kind of behavior can be achieved, but in slightly different way. You just need to use typescript interface, like:

interface IValue {     prop: string }  interface MyType {     [name: string]: IValue; } 

that will be used for example like:

var t: MyType = {}; t['field1'] = { prop: null }; t['field2'] = new DifferentType(); // compile-time error ... var val = t['field1']; val.prop = 'my prop value'; 

You don't have to create typescript class, Everything you need is a regular javascript object ( in that case {} ) and make it implement interface MyType, so it behaves like dictionary and provide you with compile-time type safety.