You can find the file with TypeScript definitions for DevExtreme in the DevExtreme zip archive or in the folder where you have installed DevExtreme, which is C:\Program Files (x86)\DevExpress 18.1\DevExtreme\Sources\Lib\ts by default. Add this file to your project. Then, reference this and jQuery TypeScript definition file in your .ts-file.
/// <reference path="TypeScript/jquery.d.ts" /> // File from the zip archive or from the installation folder... /// <reference path="TypeScript/dx.all.d.ts" /> // ...or file from GitHub /// <reference path="TypeScript/devextreme.d.ts" />
You can also reference TypeScript definitions for Knockout or AngularJS.
/// <reference path="TypeScript/knockout.d.ts" /> /// <reference path="TypeScript/angular.d.ts" />
Along with TypeScript definitions, you need to reference the libraries themselves. See Installation for detailed information.