Configuring npm/pnpm/bun

Configuring the frontend package manager.

Install a Custom Package
Switch Among npm, pnpm & bun

npm is the recommended and default package manager for Vaadin projects. This page explains how to configure npm and how to change to an alternative package manager (i.e., pnpm or bun).

Install a Custom Package

To install a custom frontend package into your project with npm, run npm i xxx. For example, to add the mobx package as a dependency in package.json as well as install it into node_modules, run the following command in the project directory:

npm i mobx

Note	Vaadin expects transitive platform dependencies to be available directly under `node_modules`. Vaadin uses the `npm` overrides feature (since `npm` 8.3.0) to lock the transitive platform dependencies versions.

Switch Among npm, pnpm & bun

npm is used as the default frontend package manager. Vaadin also supports using pnpm (also known as, performant npm). To switch to pnpm, you can set the vaadin.pnpm.enable system property to true.

When using pnpm, the framework installs it locally using npm if it isn’t installed globally. The package-lock.json file that’s used by npm is incompatible with pnpm and is removed automatically if pnpm is used. pnpm uses the pnpm-lock.yaml file instead of package-lock.json. Any custom dependency configurations should go to pnpm-lock.yaml.

Using bun is also supported by Vaadin. With bun, packages are cached locally by default and linked — instead of downloaded — for every project. This results in reduced disk space usage, and faster recurring builds compared to npm. To switch to bun, you can set the vaadin.bun.enable system property to true.

When using bun, a binary lockfile named bun.lockb is used when bun install is run. This lockfile is not included in or used from Vaadin development bundle.

Note	Vaadin does not support automatic installation of bun - instead please follow the installation instructions.

Switching in a Spring Boot Project

For a Spring Boot-based project, you can add vaadin.pnpm.enable = true or vaadin.bun.enable = true to the application.properties file.

Switching in a Plain Java or JavaEE Project

For a plain Java or a JavaEE-based project, you can set the pnpmEnable or bunEnable configuration property inside the vaadin-maven-plugin.

<plugin>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-maven-plugin</artifactId>
    <version>${project.version}</version>
    <executions>
        <execution>
            <goals>
                <goal>prepare-frontend</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <pnpmEnable>true</pnpmEnable>
    </configuration>
</plugin>

<plugin>
    <groupId>com.vaadin</groupId>
    <artifactId>vaadin-maven-plugin</artifactId>
    <version>${project.version}</version>
    <executions>
        <execution>
            <goals>
                <goal>prepare-frontend</goal>
            </goals>
        </execution>
    </executions>
    <configuration>
        <bunEnable>true</bunEnable>
    </configuration>
</plugin>

Alternatively, you can use the Servlet 3.0 @WebServlet annotation:

@WebServlet(urlPatterns = "/*", name = "myservlet", asyncSupported = true, loadOnStartup = 1,
  initParams = { @WebInitParam(name = "pnpm.enable", value = "true") })
public class CustomServlet extends VaadinServlet {
}

@WebServlet(urlPatterns = "/*", name = "myservlet", asyncSupported = true, loadOnStartup = 1,
  initParams = { @WebInitParam(name = "bun.enable", value = "true") })
public class CustomServlet extends VaadinServlet {
}

or use the traditional web.xml file:

<?xml version="1.0" encoding="UTF-8"?>
<web-app
  id="WebApp_ID" version="3.0"
  xmlns="http://java.sun.com/xml/ns/j2ee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
      http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">

  <servlet>
    <servlet-name>myservlet</servlet-name>
    <servlet-class>
        com.vaadin.flow.server.VaadinServlet
    </servlet-class>
    <load-on-startup>1</load-on-startup>

    <init-param>
      <param-name>pnpm.enable</param-name>
      <param-value>true</param-value>
    </init-param>
  </servlet>

  <servlet-mapping>
    <servlet-name>myservlet</servlet-name>
    <url-pattern>/*</url-pattern>
  </servlet-mapping>
</web-app>

<?xml version="1.0" encoding="UTF-8"?>
<web-app
  id="WebApp_ID" version="3.0"
  xmlns="http://java.sun.com/xml/ns/j2ee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
      http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">

  <servlet>
    <servlet-name>myservlet</servlet-name>
    <servlet-class>
        com.vaadin.flow.server.VaadinServlet
    </servlet-class>
    <load-on-startup>1</load-on-startup>

    <init-param>
      <param-name>bun.enable</param-name>
      <param-value>true</param-value>
    </init-param>
  </servlet>

  <servlet-mapping>
    <servlet-name>myservlet</servlet-name>
    <url-pattern>/*</url-pattern>
  </servlet-mapping>
</web-app>

For more about how to set properties, see Configuration Properties.

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