Nebula build

Build a nebula visualization bundle


nebula build


Specify a different configuration file

nebula build --config config/my-nebula-config.js

Activate file watching for changes in the source files in the /src directory, and automatically rebuild the bundle when changes are detected, with the default bundle format set to UMD

nebula build --watch

Build the bundle without generating source maps ( files)

nebula build --sourcemap false

In the development mode, the output files are not minified

nebula build --mode development

Disable the SystemJS module format bundle generation

nebula build --systemjs false

Enable core build generation, with the default output target for compiling ES modules set to ./core

nebula build --core

Enable TypeScript parsing and bundling

nebula build --typescript


—version booleanShow version number
—config, -c stringSet the path to a config file”nebula.config.js”
—watch, -w boolean|string (true|false|“umd”|“systemjs”)Rebuild bundle when its source files change on diskfalse
—sourcemap, -m booleanGenerate source mapstrue
—mode string (“production”|“development”)Set the mode
—systemjs booleanTranspile a SystemJS module format bundle for releasetrue
—core stringSet a core build target for compiling ES Modules for release”core”
—typescript booleanEnable TypeScript parsing and bundlingfalse
-h, —helpShow help for the command


Module bundler

Nebula build uses rollup.js, a module bundler, to compile the Nebula visualization code into a bundle that can be seamlessly integrated as a Qlik Sense extension.

Nebula build supports three formats, UMD (Universal Module Definition), ESM (ECMAScript modules), and SystemJS module. The UMD code is used by nebula sense. to generate Qlik Sense compatible files for use as an Extension.

Note: In your root package.json file, ensure that the main field is properly set, such as ‘your-dir/your-file.js’. As nebula build references it to determine the output location of the UMD code.

Additionally, the peerDependencies are treated by nebula build as external dependencies that are not bundled with your local JavaScript , thereby reducing the size of the bundle.

Configuration file

Nebula build CLI automatically recognizes the ‘nebula.config.js’ file in your root directory as the configuration file, you can set the path and filename of your preference with nebula build --config your-path/your-name.js command.

In the configuration file, the following build properties can be set:

  • replacementStrings
  • watch
  • sourcemap
  • mode
  • systemjs
  • core
  • typescript

replacementStrings is set to replace strings in files during bundling and the rest has the same meaning and purpose as the options preceding.

An example of setting the nebula build configuration in a config file is as follows:

const path = require("path");
const targetPkg = require(path.resolve(process.cwd(), "package.json"));
const replacementStrings = {
  "process.env.PACKAGE_VERSION": JSON.stringify(targetPkg.version),
const mode =
  process.env.NODE_ENV === "production" ? "production" : "development";
const sourcemap = mode !== "production";

module.exports = {
  build: {
    watch: true,
    systemjs: false,
    core: "core",
    typescript: true,


You can specify different watching modes using the --watch option, with values true, false, "umd", or "systemjs":

nebula build # Disable watching
nebula build --watch # Watch for changes and rebuild in UMD format
nebula build --watch umd # Watch for changes and rebuild in UMD format
nebula build --watch systemjs # Watch for changes and rebuild in SystemJS format

Source map

A source map is a file that maps from the bundled source file to the original source files, allowing the browser to reconstruct and present the original source code in the debugger. Thus, if there is an error in a file in the /dist directory, the source map can tell you the original source file location.

Source maps are primarily useful for debugging and should be removed in production.


Environment settings can be specified using the --mode parameter.

Production mode minifies all compiled modules, while development mode keeps them unminified. Minified output is the default, unless watch mode is enabled.

SystemJS build

The generation of the SystemJS module format bundle is automatically enabled by default.

To specify the output file for the SystemJS module format bundle, you should add a systemjs field in the package.json file:

"systemjs": "dist/hello.systemjs.js"

Core build

You can build an ESM bundle by adding the --core parameter. The default output target for compiling ES modules is set to ./core directory.

nebula build --core

Before running the preceding command, you should first add a package.json file in the /core directory and then specify the output file in a module field in that package.json file:

"module": "core/esm/index.js",

After running the preceding command, the ESM bundle (index.js) is exported into the /core/esm directory.

To specify another directory, move the package.json file into that directory and change the string in the module field accordingly:

"module": "minimal/target/index.js",

and run the following command:

nebula build --core minimal/target

The index.js file is exported into the /minimal/target directory.

Note: your added package.json file can have a different list of peerDependencies compared to the root package.json file, changing which dependencies are included in the ESM bundle.


With the --typescript option, you can enable TypeScript parsing and bundling for your code.

nebula build --typescript

To configure TypeScript according to your preferences, you should add a tsconfig.json file.

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