1. Visual Studio 2019 React App
2. Visual Studio 2019 Reaction
3. Visual Studio 2019 React
4. Visual Studio 2019 React Project
5. Visual Studio 2019 React Tutorial

Improving Project Load Performance Search in Watch window. The Watch window provides an advanced way to examine a variable. To watch a variable while debugging, add it to the Watch window by right-clicking the variable or the DataTip and selecting Add Watch.Now, the variable appears in the Watch window. In Visual Studio 2019, we can see the search feature inside the Watch window. Visual Studio extension development. Create add-ons and extensions for Visual Studio, including new commands, code analyzers, and tool windows. Add the SDKs and tools you need to create new commands, code analyzers, tool windows, and language services using C#. Then, share your extension with the community in the Visual Studio. Extension for Visual Studio - React code snippets for Visual Studio 2017 & 2019. Visual Studio を使って、TypeScript + React でWeb画面を作成し、C#で作ったWebAPIを呼び出す簡単なプログラムを作成する手順を紹介します。ポイントは Visual Studio をどう使うかという点です。. Debugging React Apps In Visual Studio Code By Pranav Manair Browser debugger or extension to the browser debugger is the usual way of debugging Javascript-based web applications and Javascript-based frameworks like React, Angular, etc. For React-based apps, React Developer Tools is such an extension. There is nothing wrong with this approach of.

React is a popular JavaScript library developed by Facebook for building web application user interfaces. The Visual Studio Code editor supports React.js IntelliSense and code navigation out of the box.

Welcome to React

We'll be using the create-react-appgenerator for this tutorial. To use the generator as well as run the React application server, you'll need Node.js JavaScript runtime and npm (Node.js package manager) installed. npm is included with Node.js which you can download and install from Node.js downloads.

Tip: To test that you have Node.js and npm correctly installed on your machine, you can type node --version and npm --version in a terminal or command prompt.

You can now create a new React application by typing:

where my-app is the name of the folder for your application. This may take a few minutes to create the React application and install its dependencies.

Note: If you've previously installed create-react-app globally via npm install -g create-react-app, we recommend you uninstall the package using npm uninstall -g create-react-app to ensure that npx always uses the latest version.

Let's quickly run our React application by navigating to the new folder and typing npm start to start the web server and open the application in a browser:

You should see the React logo and a link to 'Learn React' on http://localhost:3000 in your browser. We'll leave the web server running while we look at the application with VS Code.

To open your React application in VS Code, open another terminal or command prompt window, navigate to the my-app folder and type code .:

Markdown preview

In the File Explorer, one file you'll see is the application README.md Markdown file. This has lots of great information about the application and React in general. A nice way to review the README is by using the VS Code Markdown Preview. You can open the preview in either the current editor group (Markdown: Open Preview⇧⌘V (Windows, Linux Ctrl+Shift+V)) or in a new editor group to the side (Markdown: Open Preview to the Side⌘K V (Windows, Linux Ctrl+K V)). You'll get nice formatting, hyperlink navigation to headers, and syntax highlighting in code blocks.

Syntax highlighting and bracket matching

Now expand the src folder and select the index.js file. You'll notice that VS Code has syntax highlighting for the various source code elements and, if you put the cursor on a parenthesis, the matching bracket is also selected.

IntelliSense

As you start typing in index.js, you'll see smart suggestions or completions.

After you select a suggestion and type ., you see the types and methods on the object through IntelliSense.

VS Code uses the TypeScript language service for its JavaScript code intelligence and it has a feature called Automatic Type Acquisition (ATA). ATA pulls down the npm Type Declaration files (*.d.ts) for the npm modules referenced in the package.json.

If you select a method, you'll also get parameter help:

Go to Definition, Peek definition

Through the TypeScript language service, VS Code can also provide type definition information in the editor through Go to Definition (F12) or Peek Definition (⌥F12 (Windows Alt+F12, Linux Ctrl+Shift+F10)). Put the cursor over the App, right click and select Peek Definition. A Peek window will open showing the App definition from App.js.

Press Escape to close the Peek window.

Hello World!

Let's update the sample application to 'Hello World!'. Create a new H1 header with 'Hello, world!' and replace the <App /> tag in ReactDOM.render with element.

Once you save the index.js file, the running instance of the server will update the web page and you'll see 'Hello World!' when you refresh your browser.

Tip: VS Code supports Auto Save, which by default saves your files after a delay. Check the Auto Save option in the File menu to turn on Auto Save or directly configure the files.autoSave user setting.

Debugging React

To debug the client side React code, we'll need to install the Debugger for Chrome extension.

Note: This tutorial assumes you have the Chrome browser installed. There are also debugger extensions for the Edge and Firefox browsers.

Open the Extensions view (⇧⌘X (Windows, Linux Ctrl+Shift+X)) and type 'chrome' in the search box. You'll see several extensions which reference Chrome.

Press the Install button for Debugger for Chrome.

Set a breakpoint

To set a breakpoint in index.js, click on the gutter to the left of the line numbers. This will set a breakpoint which will be visible as a red circle.

Configure the Chrome debugger

We need to initially configure the debugger. To do so, go to the Run view (⇧⌘D (Windows, Linux Ctrl+Shift+D)) and click create a launch.json file to customize Run and Debug. Choose Chrome from the Select Environment dropdown list. This will create a launch.json file in a new .vscode folder in your project which includes a configuration to launch the website.

We need to make one change for our example: change the port of the url from 8080 to 3000. Your launch.json should look like this:

Ensure that your development server is running (npm start). Then press F5 or the green arrow to launch the debugger and open a new browser instance. The source code where the breakpoint is set runs on startup before the debugger was attached, so we won't hit the breakpoint until we refresh the web page. Refresh the page and you should hit your breakpoint.

You can step through your source code (F10), inspect variables such as element, and see the call stack of the client side React application.

The Debugger for Chrome extension README has lots of information on other configurations, working with sourcemaps, and troubleshooting. You can review it directly within VS Code from the Extensions view by clicking on the extension item and opening the Details view.

Live editing and debugging

If you are using webpack together with your React app, you can have a more efficient workflow by taking advantage of webpack's HMR mechanism which enables you to have live editing and debugging directly from VS Code. You can learn more in this Live edit and debug your React apps directly from VS Code blog post and the webpack Hot Module Replacement documentation.

Linting

Linters analyze your source code and can warn you about potential problems before you run your application. The JavaScript language services included with VS Code has syntax error checking support by default, which you can see in action in the Problems panel (View > Problems⇧⌘M (Windows, Linux Ctrl+Shift+M)).

Try making a small error in your React source code and you'll see a red squiggle and an error in the Problems panel.

Linters can provide more sophisticated analysis, enforcing coding conventions and detecting anti-patterns. A popular JavaScript linter is ESLint. ESLint, when combined with the ESLint VS Code extension, provides a great in-product linting experience.

First, install the ESLint command-line tool:

Then install the ESLint extension by going to the Extensions view and typing 'eslint'.

Once the ESLint extension is installed and VS Code reloaded, you'll want to create an ESLint configuration file, .eslintrc.js. You can create one using the extension's ESLint: Create ESLint configuration command from the Command Palette (⇧⌘P (Windows, Linux Ctrl+Shift+P)).

The command will prompt you to answer a series of questions in the Terminal panel. Take the defaults, and it will create a .eslintrc.js file in your project root that looks something like this:

ESLint will now analyze open files and shows a warning in index.js about 'App' being defined but never used.

You can modify the ESLint rules in the .eslintrc.js file.

Let's add an error rule for extra semi-colons:

Now when you mistakenly have multiple semicolons on a line, you'll see an error (red squiggle) in the editor and error entry in the Problems panel.

Popular Starter Kits

In this tutorial, we used the create-react-app generator to create a simple React application. There are lots of great samples and starter kits available to help build your first React application.

VS Code React Sample

This is a sample React application used for a demo at the 2016 //Build conference. The sample creates a simple TODO application and includes the source code for a Node.js Express server. It also shows how to use the Babel ES6 transpiler and then use webpack to bundle the site assets.

TypeScript React

If you're curious about TypeScript and React, you can also create a TypeScript version of the create-react-app application by specifying that you want to use the TypeScript template:

See the details at Adding TypeScript on the Create React App site.

Angular

Angular is another popular web framework. If you'd like to see an example of Angular working with VS Code, check out the Chrome Debugging with Angular CLI recipe. It will walk you through creating an Angular application and configuring the launch.json file for the Debugger for Chrome extension.

Common questions

Can I get IntelliSense within declarative JSX?

Yes. For example, if you open the create-react-app project's App.js file, you can see IntelliSense within the React JSX in the render() method.

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Visual Studio allows you to easily create a Node.js project and experience IntelliSense and other built-in features that support Node.js. In this tutorial for Visual Studio, you create a Node.js web application project from a Visual Studio template. Then, you create a simple app using React.

In this tutorial, you learn how to:

• Create a Node.js project
• Add npm packages
• Add React code to your app
• Transpile JSX
• Attach the debugger

Before you begin

Here's a quick FAQ to introduce you to some key concepts.

What is Node.js?

Visual Studio 2019 React App

Node.js is a server-side JavaScript runtime environment that executes JavaScript server-side.

What is npm?

npm is the default package manager for the Node.js. The package manager makes it easier for programmers to publish and share source code of Node.js libraries and is designed to simplify installation, updating, and uninstallation of libraries.

What is React?

React is a front-end framework to create a UI.

What is JSX?

JSX is a JavaScript syntax extension, typically used with React to describe UI elements. JSX code must be transpiled to plain JavaScript before it can run in a browser.

What is webpack?

webpack bundles JavaScript files so they can run in a browser. It can also transform or package other resources and assets. It is often used to specify a compiler, such as Babel or TypeScript, to transpile JSX or TypeScript code to plain JavaScript.

Prerequisites

• You must have Visual Studio installed and the Node.js development workload.

  If you haven't already installed Visual Studio 2019, go to the Visual Studio downloads page to install it for free.

  If you haven't already installed Visual Studio 2017, go to the Visual Studio downloads page to install it for free.

  If you need to install the workload but already have Visual Studio, go to Tools > Get Tools and Features..., which opens the Visual Studio Installer. Choose the Node.js development workload, then choose Modify.

• You must have the Node.js runtime installed.

  This tutorial was tested with version 12.6.2.

  If you don't have it installed, we recommend you install the LTS version from the Node.js website for best compatibility with outside frameworks and libraries. Node.js is built for 32-bit and 64-bit architectures. The Node.js tools in Visual Studio, included in the Node.js workload, support both versions. Only one is required and the Node.js installer only supports one being installed at a time.

  In general, Visual Studio automatically detects the installed Node.js runtime. If it does not detect an installed runtime, you can configure your project to reference the installed runtime in the properties page (after you create a project, right-click the project node, choose Properties, and set the Node.exe path). You can use a global installation of Node.js or you can specify the path to a local interpreter in each of your Node.js projects.

Create a project

First, create a Node.js web application project.

1. Open Visual Studio.

2. Create a new project.

   Press Esc to close the start window. Type Ctrl + Q to open the search box, type Node.js, then choose Blank Node.js Web Application - JavaScript. (Although this tutorial uses the TypeScript compiler, the steps require that you start with the JavaScript template.)

   In the dialog box that appears, choose Create.

   From the top menu bar, choose File > New > Project. In the left pane of the New Project dialog box, expand JavaScript, then choose Node.js. In the middle pane, choose Blank Node.js Web Application, type the name NodejsWebAppBlank, then choose OK.

   If you don't see the Blank Node.js Web Application project template, you must add the Node.js development workload. For detailed instructions, see the Prerequisites.

   Visual Studio creates the new solution and opens your project.

   (1) Highlighted in bold is your project, using the name you gave in the New Project dialog box. In the file system, this project is represented by a .njsproj file in your project folder. You can set properties and environment variables associated with the project by right-clicking the project and choosing Properties. You can do round-tripping with other development tools, because the project file does not make custom changes to the Node.js project source.

   (2) At the top level is a solution, which by default has the same name as your project. A solution, represented by a .sln file on disk, is a container for one or more related projects.

   (3) The npm node shows any installed npm packages. You can right-click the npm node to search for and install npm packages using a dialog box or install and update packages using the settings in package.json and right-click options in the npm node.

   (4) package.json is a file used by npm to manage package dependencies and package versions for locally-installed packages. For more information, see Manage npm packages.

   (5) Project files such as server.js show up under the project node. server.js is the project startup file and that is why it shows up in bold. You can set the startup file by right-clicking a file in the project and selecting Set as Node.js startup file.

Add npm packages

This app requires a number of npm modules to run correctly.

• react
• react-dom
• express
• path
• ts-loader
• typescript
• webpack
• webpack-cli

1. In Solution Explorer (right pane), right-click the npm node in the project and choose Install New npm Packages.

   In the Install New npm Packages dialog box, you can choose to install the most current package version or specify a version. If you choose to install the current version of these packages, but run into unexpected errors later, you may want to install the exact package versions described later in these steps.

2. In the Install New npm Packages dialog box, search for the react package, and select Install Package to install it.

   Select the Output window to see progress on installing the package (select Npm in the Show output from field). When installed, the package appears under the npm node.

   The project's package.json file is updated with the new package information including the package version.

3. Instead of using the UI to search for and add the rest of the packages one at a time, paste the following code into package.json. To do this, add a dependencies section with this code:

   If there is already a dependencies section in your version of the blank template, just replace it with the preceding JSON code. For more information on use of this file, see package.json configuration.

4. Save the changes.

5. Right-click npm node in your project and choose Install npm Packages.

   This command runs the npm install command directly.

   In the lower pane, select the Output window to see progress on installing the packages. Installation may take a few minutes and you may not see results immediately. To see the output, make sure that you select Npm in the Show output from field in the Output window.

   Here are the npm modules as they appear in Solution Explorer after they are installed.

   Note

   If you prefer to install npm packages using the command line, right-click the project node and choose Open Command Prompt Here. Use standard Node.js commands to install packages.

Add project files

In these steps, you add four new files to your project.

• app.tsx
• webpack-config.js
• index.html
• tsconfig.json

For this simple app, you add the new project files in the project root. (In most apps, you typically add the files to subfolders and adjust relative path references accordingly.)

1. In Solution Explorer, right-click the project NodejsWebAppBlank and choose Add > New Item.

2. In the Add New Item dialog box, choose TypeScript JSX file, type the name app.tsx, and select Add or OK.

3. Repeat these steps to add webpack-config.js. Instead of a TypeScript JSX file, choose JavaScript file.

4. Repeat the same steps to add index.html to the project. Instead of a JavaScript file, choose HTML file.

5. Repeat the same steps to add tsconfig.json to the project. Instead of a JavaScript file, choose TypeScript JSON Configuration file.

Add app code

1. Open server.js and replace the existing code with the following code:

   The preceding code uses Express to start Node.js as your web application server. This code sets the port to the port number configured in the project properties (by default, the port is configured to 1337 in the properties). To open the project properties, right-click the project in Solution Explorer and choose Properties.

2. Open app.tsx and add the following code:

   The preceding code uses JSX syntax and React to display a simple message.

3. Open index.html and replace the body section with the following code:

   This HTML page loads app-bundle.js, which contains the JSX and React code transpiled to plain JavaScript. Currently, app-bundle.js is an empty file. In the next section, you configure options to transpile the code.

Configure webpack and TypeScript compiler options

In the previous steps, you added webpack-config.js to the project. Next, you add webpack configuration code. You will add a simple webpack configuration that specifies an input file (app.tsx) and an output file (app-bundle.js) for bundling and transpiling JSX to plain JavaScript. For transpiling, you also configure some TypeScript compiler options. This code is a basic configuration that is intended as an introduction to webpack and the TypeScript compiler.

1. In Solution Explorer, open webpack-config.js and add the following code.

   The webpack configuration code instructs webpack to use the TypeScript loader to transpile the JSX.

2. Open tsconfig.json and replace the default code with the following code, which specifies the TypeScript compiler options:

   app.tsx is specified as the source file.

Visual Studio 2019 Reaction

Transpile the JSX

1. In Solution Explorer, right-click the project node and choose Open Command Prompt Here.

2. In the command prompt, type the following command:

   node_modules.binwebpack app.tsx --config webpack-config.js

   The command prompt window shows the result.

   If you see any errors instead of the preceding output, you must resolve them before your app will work. If your npm package versions are different than the versions shown in this tutorial, that can be a source of errors. One way to fix errors is to use the exact versions shown in the earlier steps. Also, if one or more of these package versions has been deprecated and results in an error, you may need to install a more recent version to fix errors. For information on using package.json to control npm package versions, see package.json configuration.

3. In Solution Explorer, right-click the project node and choose Add > Existing Folder, then choose the dist folder and choose Select Folder.

   Visual Studio adds the dist folder to the project, which contains app-bundle.js and app-bundle.js.map.

4. Open app-bundle.js to see the transpiled JavaScript code.

5. If prompted to reload externally modified files, select Yes to All.

Each time you make changes to app.tsx, you must rerun the webpack command. To automate this step, add a build script to transpile the JSX.

Add a build script to transpile the JSX

Starting in Visual Studio 2019, a build script is required. Instead of transpiling JSX at the command line (as shown in the preceding section), you can transpile JSX when building from Visual Studio.

• Open package.json and add the following section after the dependencies section:

Run the app

1. Select either Web Server (Google Chrome) or Web Server (Microsoft Edge) as the current debug target.

   If Chrome is available on your machine, but does not show up as an option, choose Browse With from the debug target dropdown list, and select Chrome as the default browser target (choose Set as Default).

2. To run the app, press F5 (Debug > Start Debugging) or the green arrow button.

   A Node.js console window opens that shows the port on which the debugger is listening.

   Visual Studio starts the app by launching the startup file, server.js.

3. Close the browser window.

4. Close the console window.

Set a breakpoint and run the app

1. In server.js, click in the gutter to the left of the staticPath declaration to set a breakpoint:

   Breakpoints are the most basic and essential feature of reliable debugging. A breakpoint indicates where Visual Studio should suspend your running code so you can take a look at the values of variables, or the behavior of memory, or whether or not a branch of code is getting run.

2. To run the app, press F5 (Debug > Start Debugging).

   The debugger pauses at the breakpoint you set (the current statement is marked in yellow). Now, you can inspect your app state by hovering over variables that are currently in scope, using debugger windows like the Locals and Watch windows.

3. Press F5 to continue the app.

4. If you want to use the Chrome Developer Tools or F12 Tools for Microsoft Edge, press F12. You can use these tools to examine the DOM and interact with the app using the JavaScript Console.

5. Close the web browser and the console.

Set and hit a breakpoint in the client-side React code

Visual Studio 2019 React

In the preceding section, you attached the debugger to server-side Node.js code. To attach the debugger from Visual Studio and hit breakpoints in client-side React code, the debugger needs help to identify the correct process. Here is one way to enable this.

Prepare the browser for debugging

For this scenario, use either Microsoft Edge (Chromium), currently named Microsoft Edge Beta in the IDE, or Chrome.

1. Close all windows for the target browser.

   Other browser instances can prevent the browser from opening with debugging enabled. (Browser extensions may be running and preventing full debug mode, so you may need to open Task Manager to find unexpected instances of Chrome.)

   For Microsoft Edge (Chromium), also shut down all instances of Chrome. Because both browsers share the chromium code base, this gives the best results.

2. Start your browser with debugging enabled.

   Starting in Visual Studio 2019, you can set the --remote-debugging-port=9222 flag at browser launch by selecting Browse With... > from the Debug toolbar, then choosing Add, and then setting the flag in the Arguments field. Use a different friendly name for the browser such as Edge with Debugging or Chrome with Debugging. For details, see the Release Notes.

   Alternatively, open the Run command from the Windows Start button (right-click and choose Run), and enter the following command:

   msedge --remote-debugging-port=9222

   or,

   chrome.exe --remote-debugging-port=9222

   Open the Run command from the Windows Start button (right-click and choose Run), and enter the following command:

   chrome.exe --remote-debugging-port=9222

   This starts your browser with debugging enabled.

   The app is not yet running, so you get an empty browser page.

Attach the debugger to client-side script

Visual Studio 2019 React Project

1. Switch to Visual Studio and then set a breakpoint in your source code, either app-bundle.js or app.tsx.

   For app-bundle.js, set the breakpoint in the render() function as shown in the following illustration:

   To find the render() function in the transpiled app-bundle.js file, use Ctrl+F (Edit > Find and Replace > Quick Find).

   For app.tsx, set the breakpoint inside the render() function, on the return statement.

2. If you are setting the breakpoint in the .tsx file (rather than app-bundle.js), you need to update webpack-config.js. Replace the following code:

   with this code:

   This is a development-only setting to enable debugging in Visual Studio. This setting allows you to override the generated references in the source map file, app-bundle.js.map, when building the app. By default, webpack references in the source map file include the webpack:/// prefix, which prevents Visual Studio from finding the source file, app.tsx. Specifically, when you make this change, the reference to the source file, app.tsx, gets changed from webpack:///./app.tsx to ./app.tsx, which enables debugging.

3. Select your target browser as the debug target in Visual Studio, then press Ctrl+F5 (Debug > Start Without Debugging) to run the app in the browser.

   If you created a browser configuration with a friendly name, choose that as your debug target.

   The app opens in a new browser tab.

4. Choose Debug > Attach to Process.

   Tip

   Starting in Visual Studio 2017, once you attach to the process the first time by following these steps, you can quickly reattach to the same process by choosing Debug > Reattach to Process.

5. In the Attach to Process dialog box, get a filtered list of browser instances that you can attach to.

   In Visual Studio 2019, choose the correct debugger for your target browser, JavaScript (Chrome) or JavaScript (Microsoft Edge - Chromium) in the Attach to field, type chrome or edge in the filter box to filter the search results.

   In Visual Studio 2017, choose Webkit code in the Attach to field, type chrome in the filter box to filter the search results.

6. Select the browser process with the correct host port (localhost in this example), and select Attach.

   The port (1337) may also appear in the Title field to help you select the correct browser instance.

   The following example shows how this looks for the Microsoft Edge (Chromium) browser.

   You know the debugger has attached correctly when the DOM Explorer and the JavaScript Console open in Visual Studio. These debugging tools are similar to Chrome Developer Tools and F12 Tools for Microsoft Edge.

   Tip

   If the debugger does not attach and you see the message 'Unable to attach to the process. An operation is not legal in the current state.', use the Task Manager to close all instances of the target browser before starting the browser in debugging mode. Browser extensions may be running and preventing full debug mode.

7. Because the code with the breakpoint already executed, refresh your browser page to hit the breakpoint.

   While paused in the debugger, you can examine your app state by hovering over variables and using debugger windows. You can advance the debugger by stepping through code (F5, F10, and F11). For more information on basic debugging features, see First look at the debugger.

   You may hit the breakpoint in either app-bundle.js or its mapped location in app.tsx, depending on which steps you followed previously, along with your environment and browser state. Either way, you can step through code and examine variables.

   • If you need to break into code in app.tsx and are unable to do it, use Attach to Process as described in the previous steps to attach the debugger. Make sure you that your environment is set up correctly:

     • You closed all browser instances, including Chrome extensions (using the Task Manager), so that you can run the browser in debug mode. Make sure you start the browser in debug mode.

     • Make sure that your source map file includes a reference to ./app.tsx and not webpack:///./app.tsx, which prevents the Visual Studio debugger from locating app.tsx.Alternatively, if you need to break into code in app.tsx and are unable to do it, try using the debugger; statement in app.tsx, or set breakpoints in the Chrome Developer Tools (or F12 Tools for Microsoft Edge) instead.

   • If you need to break into code in app-bundle.js and are unable to do it, remove the source map file, app-bundle.js.map.

Visual Studio 2019 React Tutorial

Next steps