Learn TypeScript 3 by Building Web Applications

Defining the view contract

Let's define our contract.

Do the following inside src/views and create a file called world-explorer-view.intf.ts.

Here's the interface definition that we'll use:

import {Country} from "../domain"; 

import {ChartDetails} from "./chart-details.intf"; 


export interface WorldExplorerView { 
    displayErrorMessage(message: string): void; 
    displayCountries(countries: Country[]): void; 
    displayYears(years: number[]): void; 
    getChartFormDetails(): { error?: string, countryId?: string,      indicator?: string, fromYear?: number,      toYear?: number, chartType?: string}; 
    displayChart(chartDetails: ChartDetails): void; 
} 

For the return type of the getChartFormDetails method, we are using the same trick as in the last chapter, allowing us ...