title: Accessing index in Typescript Interface
body: <p>I have created a Dictionary in Typescript using index types and i'm trying to use it somewhere in my code. But can't figure out how can access the index. I have two interfaces:</p>
  <pre><code>export interface OrderForm {
   model_id?: number;
   model_color_id?: number;
   model_product_id?: number;
   total_lld: ComputedTotalLLDOptions;
   product_parts_id?: string;
  }
  
  export interface ComputedTotalLLDOptions {
    [index: number]: {
      contribution: number;
      duration: number;
      rent: number;
    };
  }
  </code></pre>
  <p>Do you have some example of how can i use it ?</p>