Step 2 - create MockSharePointClient

Create another file, called MockSharePointClient.ts in the same folder where the web part is located.

import { ISPListItem } from "./ISPListItem"; 
 
export default class MockSharePointClient { 
    private static _listItems: ISPListItem[] = [ 
      { Id: 1, Title: "First list item" }, 
      { Id: 2, Title: "Second list item" }, 
      { Id: 3, Title: "Third list item" }, 
      { Id: 4, Title: "Fourth list item" }, 
      { Id: 5, Title: "Fifth list item" }, 
      { Id: 6, Title: "Sixth list item" }, 
      { Id: 7, Title: "Seventh list item" }, 
      { Id: 8, Title: "Eight list item" }, 
      { Id: 9, Title: "Ninth list item" }, 
    ]; 
    public static get(restUrl: string, options?: any) 
       : Promise<ISPListItem[]> { 
            return new Promise<ISPListItem[]>((resolve) => { 
            resolve(MockSharePointClient._listItems...