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Function roles

A package can contain functions that get discovered and integrated with the platform at runtime. Typically, each function type has a special tag denoting what the function does, for example:

You can use these tags to search for certain functions either from the platform's interface ( or from within your code:

const applications = DG.Func.find({tags: [DG.FUNC_TYPES.APP]});

TIP To disable all package functions (for debug purposes), use the initPackageFunctions=false flag in the start URL, such as


Applications are functions tagged with the #app tag. Use datagrok-tools to get a template:

cd <package-name>
grok add app <name>

Details: How to build an application

Info panels

Functions tagged as #panel extend the context panel with additional content for the current object. Use datagrok-tools to get a template:

cd <package-name>
grok add function panel <name>
grok add script panel <language> <name>

Details: How to add an info panel

Package initialization

init function gets invoked before the first time any of the package functions is invoked. This is a good place to initialize some common structures (load WebAssembly, fetch files) that some of exposed functions use. It gets invoked at most once.

Use datagrok-tools to get a template:

cd <package-name>
grok add function init <packageName>Init

See also autostart.


autostart function get invoked at platform startup. It starts immediately if it is tagged as meta.autostartImmediate: true, otherwise it starts three seconds later.

Use the meta.autostartImmediate: true mode is good to subscribe to global events, change some default settings, or change the UI right at the platform start. The default mode is good for preloading popular big packages (for instance, Chem package preloads to eliminate the delays when a user opens a file with molecules). Keep in mind that some packages are big, and unless the autostart function resides in the detectors.js file, the whole content of the package gets loaded, so use this option wisely.

The autostart function can reside in the detectors.js file, in which case full package content is not loaded. You might want to use it to quickly add some menu items or start listening to some events, and then you can load the full package only when a user launches that functionality.

If the autostart function is defined in the package where the init is also defined, the init function gets executed first. No one awaits on the autostart function. You might have zero, one, or more autostart functions in a package.

Example from the PowerPack plugin that introduces a "Welcome" view at startup:

//name: welcomeView
//tags: autostart
//meta.autostartImmediate: true
export function _welcomeView(): void {
if (_properties['showWelcomeView'])

Semantic type detectors

Functions that define semantic types have the #semTypeDetector tag. Use datagrok-tools to get a template:

cd <package-name>
grok add detector <semantic-type-name>

Details: How to define semantic type detectors

Cell renderers

Cell renderers allow customizing the appearance of cells in the grid. These functions are annotated with two special tags: cellRenderer and cellRenderer-<type>.

Details: How to develop custom cell renderers

File viewers

File viewers are used in Datagrok's file share browser. The platform provides a way to define custom viewers (or editors) in addition to the native ones. These functions work on files with a specific extension, which is derived from the fileViewer-<extension> tag.

Details: How to develop custom file viewers

File exporters

A file exporter is a function used for loading data from the platform. It is annotated with the #fileExporter tag. Exporters reside in the platform's top menu "export" section.

Details: How to create file exporters

Settings editors

Settings editors work with package properties and define how they will be displayed in the Settings pane of the context panel. An editor function should return a widget (DG.Widget) and be tagged as #packageSettingsEditor.

Details: How to write custom package settings editors