npm install --save-dev jest //json { "scripts": { "test": "jest" } } npm test //mock dom npm install --save-dev jest-environment-jsdom /** * @jest-environment jsdom */ //jest-localstorage-mock npm i --save-dev jest-localstorage-mock { "name": "to-do-list", "version": "1.0.0", "description": "<a name=\"To Do List\"></a>", "private": true, "jest": { "resetMocks": false, "setupFiles": [ "jest-localstorage-mock" ] }, "scripts": { "test": "jest",... //Babel npm install --save-dev @babel/plugin-transform-modules-commonjs //create a new file in the project root directory called: .babelrc with the following code in it: { "env": { "test": { "plugins": ["@babel/plugin-transform-modules-commonjs"] } } } //REACT npm install --save-dev react-test-renderer jest --updateSnapshot //auto complete : npm install @types/jest