If you are using Maven or Gradle, add the following dependency to the dependencies section of your project descriptor to access the Vert.x Core API and enable the JavaScript support:

- Maven (in your `pom.xml`):

    <dependency>
    <groupId>io.vertx</groupId>
    <artifactId>vertx-core</artifactId>
    <version>3.9.2</version>
    </dependency>
    <dependency>
     <groupId>io.vertx</groupId>
     <artifactId>vertx-lang-kotlin</artifactId>
     <version>3.9.2</version>
    </dependency>

- Gradle (in your `build.gradle` file):

    compile "io.vertx:vertx-core:3.9.2"
    compile "io.vertx:vertx-lang-kotlin:3.9.2"