Cheat Codes

Cheat codes are meant to expose functionality that shouldn’t otherwise be available. They can be activated by passing cheatCodesEnabled as an option to the HiGlassComponent and then typing a string when a higlass window is visible.

  • “hgedit”: Toggle the header and make the higlass component editable.


To run the tests use:

npm run test-watch

To only run specific test suites, open karma.conf.js and select which tests to run.

All http requests can be automatically mocked and their responses stored in test/mocked-responses. This makes it possible to use a local higlass server when adding new tests. New tests that use data which has not been already stored, should be run a few times locally in order to mock all occuring http requests.

Please note: When adding new viewConfigs that make use of mocked responses, make sure that links do not start with // but with http(s)://. The mocking library fetch-mock that we are using, does not support links without protocol. In order get started with mocked responses, follow the setup of FetchMockHelper as in DenseDataExtremaTests.

JSON Schema

There are unit tests that validate all the viewconfs that have been checked in as fixtures. If you want to validate just one viewconf by hand:

npm install -g ajv-cli
ajv validate -s app/schema.json -d docs/examples/viewconfs/default.json


Use the following template and replace individual it blocks to set up new tests. Add this code to the tests directory and add a line to karma.conf.js to include it in the tests.

/* eslint-env node, jasmine */
import {
  // render,
} from 'enzyme';

import Adapter from 'enzyme-adapter-react-16';

import { expect } from 'chai';

// Utils
import {
} from '../app/scripts/utils';

configure({ adapter: new Adapter() });

describe('Horizontal heatmaps', () => {
  let hgc = null;
  let div = null;

  beforeAll((done) => {
    ([div, hgc] = mountHGComponent(div, hgc,
        style: 'width:800px; height:400px; background-color: lightgreen',
        bounded: true,

  it('should respect zoom limits', () => {
    // add your tests here

    const trackObj = getTrackObjectFromHGC(hgc.instance(), 'vv', 'tt');

  afterAll(() => {

// enter either a viewconf link or a viewconf object
const viewconf = {
  "editable": true,
  "zoomFixed": false,
  "trackSourceServers": [
  "exportViewUrl": "/api/v1/viewconfs/",
  "views": [
      "tracks": {}
      "uid": "vv"

Convenience Functions

To get the track object associated with a view and track uid:

import {
} from '../app/scripts/utils';

const trackObj = getTrackObjectFromHGC(hgc.instance(),
    'view_uid', 'track_uid')

Contributor Guidelines

Contributions are in the form of issues, code, documentation are always very welcome. The following are a set of guidelines to help ensure that contributions can be smoothly merged into the existing code base:

  1. All code contributions should be accompanied by a test. Tests can be placed into the test folder.
  2. All added functions should include a jsdoc string for javascript code or a numpy style docstring for python code.