Metadata-Version: 2.1
Name: jbrowse-jupyter
Version: 1.4.0
Summary: Jupyter Notebooks extension for showing JBrowse views
Home-page: https://github.com/GMOD/jbrowse-jupyter
Author: Teresa De Jesus Martinez
Author-email: tere486martinez@gmail.com
Maintainer: Teresa De Jesus Martinez; JBrowse Team
Maintainer-email: tere486martinez@gmail.com
License: Apache-2.0
Project-URL: Bug Tracker, https://github.com/GMOD/jbrowse-jupyter/issues
Classifier: Programming Language :: Python :: 3
Classifier: Topic :: Scientific/Engineering
Classifier: Intended Audience :: Science/Research
Classifier: Topic :: Scientific/Engineering :: Bio-Informatics
Requires-Python: >=3.6
Description-Content-Type: text/markdown
License-File: LICENSE
Requires-Dist: dash (>=2.11.1)
Requires-Dist: dash-jbrowse (>=1.2.0)
Requires-Dist: jupyter-dash (>=0.4.2)
Requires-Dist: Werkzeug (==2.0.3)
Requires-Dist: pandas (>=1.1.5)

![Pytest and flake8](https://github.com/GMOD/jbrowse-jupyter/actions/workflows/push.yml/badge.svg)
[![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/GMOD/jbrowse-jupyter/blob/main/browser.ipynb)
[![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/GMOD/jbrowse-jupyter/binder_updates?labpath=binder%2Fbinder.ipynb)
[![Downloads](https://pepy.tech/badge/jbrowse-jupyter)](https://pepy.tech/project/jbrowse-jupyter)
[![made-with-sphinx-doc](https://img.shields.io/badge/Made%20with-Sphinx-1f425f.svg)](https://gmod.github.io/jbrowse-jupyter/docs/html/index.html)

# [JBrowse Jupyter](https://gmod.github.io/jbrowse-jupyter/)

JBrowse Jupyter is a python package that provides a python interface to JBrowse
views.

The package provides a JBrowseConfig API to enable the creation of JBrowse state
configuration objects. It also provides utility functions to create and embed
Dash JBrowse components in jupyter notebooks and python applications.

![demo-gif](https://user-images.githubusercontent.com/45598764/144863573-2bcd982b-1d18-4dc8-aa2f-fd8adf4985a2.gif)

_You can open this browser.ipynb in colab_
[here](https://colab.research.google.com/github/GMOD/jbrowse-jupyter/blob/main/browser.ipynb)

> ### Dash JBrowse
>
> JBrowse Jupyter uses [Dash JBrowse](https://github.com/GMOD/dash_jbrowse),
> which is a collection of Dash components for JBrowse's embeddable React
> components.
>
> We utilize the Dash JBrowse package along with the
> [jupyter-dash](https://github.com/plotly/jupyter-dash) library to embed
> [JBrowse React Linear Genome view](https://www.npmjs.com/package/@jbrowse/react-linear-genome-view)
> or the
> [JBrowse React Circular Genome view](https://www.npmjs.com/package/@jbrowse/react-circular-genome-view)
> in any jupyter notebook.
>
> To learn more about the Dash JBrowse package, including how the Dash
> components can be used outside of Jupyter Notebooks, see
> [here](https://github.com/GMOD/dash_jbrowse).

## Demos

- Browser notebook demo -
  https://colab.research.google.com/github/GMOD/jbrowse-jupyter/blob/main/browser.ipynb
- SK-BR-3 demo -
  https://colab.research.google.com/github/GMOD/jbrowse-jupyter/blob/main/skbr3.ipynb

## Documentation

Additional details and tutorials can be found in our Sphinx documentation page.
https://gmod.github.io/jbrowse-jupyter/docs/html/index.html

## Installation

`jbrowse-jupyter` is freely available for download on the Python Package Index
https://pypi.org/project/jbrowse-jupyter/

```
$ pip install jbrowse-jupyter
```

## Quickstart

For all of the following examples, make sure that the JBrowse Jupyter package
has been installed into your environment (pipenv, venv, conda, etc.).

### In a Jupyter Notebook

_Launching a Linear Genome View in Jupyter Notebook_
![Launching hg38 LGV in python notebook](https://github.com/GMOD/jbrowse-jupyter/raw/main/images/notebook.png)

_Launching a Circular Genome View in Jupyter Notebook_
![Launching hg19 CGV in python notebook](https://github.com/GMOD/jbrowse-jupyter/raw/main/images/notebook2.png)
_JBrowse Linear Genome view in python Dash application_

```python
from dash import html, Dash
from jbrowse_jupyter import create, create_component

app = Dash(__name__)

jbrowse_conf = create("LGV", genome="hg38")

config = jbrowse_conf.get_config()

component = create_component(config)

app.layout = html.Div(
    [component],
    id='test'
)

if __name__ == "__main__":
    app.run_server(port=8081, debug=True)

```

### Using jupyter-server-proxy

or using the
[jupyter-server-proxy extension](https://github.com/jupyterhub/jupyter-server-proxy)
and the [jupyter-dash extension](https://github.com/plotly/jupyter-dash)

```
$ pip install jupyter-server-proxy
$ pip install jupyter-dash
```

```python
from jupyter_dash import JupyterDash

from dash import html
from jbrowse_jupyter import create, create_component
import jupyter_server_proxy

JupyterDash.infer_jupyter_proxy_config()
#JupyterDash()._server_proxy # true if the proxy works as expected
#JupyterDash().config # gives the proxy config

app = JupyterDash(__name__)
jbrowse_conf = create("LGV", genome="hg38")

config = jbrowse_conf.get_config()
component = create_component(config)

app.layout = html.Div(
    [component],
    id='test'
)

if __name__ == "__main__":
    # the external mode should display a url proxied by jupyter-server-proxy,
    # very handy on jupyterlab behind jupyterhub as in departmental jupyterlab instances.

    app.run_server(mode='external', debug=True, port=8999)

```

![Dash JBrowse LGV in python app](https://github.com/GMOD/jbrowse-jupyter/raw/main/images/python_app.png)
You can customize the Linear Genome View by modifying the `jbrowse_conf`. The
`jbrowse_conf` is an instance of our `JBrowseConfig`, and can be modified to set
an assembly, add tracks, set custom color palettes and more.

Find more information about the JBrowseConfig API
[here](https://gmod.github.io/jbrowse-jupyter/docs/html/index.html)

## Other Examples

You can find examples in the root of this repo or in the examples folder,

- `browser.py` - uses the Dash library to create a python application with the
  Dash JBrowse LinearGenomeView component
- `browser.ipynb` - jupyter notebook using the JupyterDash library to embed a
  Dash JBrowse LinearGenomeView component in a cell
- `examples/cgv_examples.py` - uses the Dash library to create a python
  application with the Dash JBrowse CircularGenomeView component
- `examples/cgv_examples.ipynb` - jupyter notebook using the JupyterDash library
  to embed a Dash JBrowse CircularGenomeView component in a cell
- `local_support.ipynb` - jupyter notebook with tutorial on using your local
  data and passing it to JBrowse views

### To run a Python Dash application

```
$ python browser.py
```

### To run a jupyter notebook

Make sure you have [jupyter notebook or jupyterlab](https://jupyter.org/install)
installed.

```
# May look different if you have classic notebooks instead of jupyterlab
jupyter-lab build
jupyter-lab browser.ipynb
```

## Usage

The `jbrowse-jupyter` package provides several utility functions to create and
launch Dash JBrowse components in python applications and jupyter notebooks.

### Configuring Components

- `create`(view_type, \*\*kwargs)- creates a JBrowseConfig configuration object
  given a view_type
  - view*type: Choose from a LGV or CGV e.g `create`('LGV') or `create`('CGV')
    Additional params: - genome: choose from one of our default genomes {hg19 or
    hg38} e.g `create`('LGV', genome="hg38") OR - conf: use a conf object, you
    can manually edit and pass json object. e.g `create`('LGV', conf={"my-conf":
    "object"}) > **Note**: you can manually create a conf following the
    https://jbrowse.org/jb2/docs/config_guide/ - if no genome or conf is passed,
    you will create an empty JBrowseConfig for that view type. \_defaults* if
    you pass no params, an empty JBrowse config for a LGV (LinearGenomeView)
    will be created
- `create_component`(conf, \*\*kwargs) - creates and returns a Dash JBrowse
  component -> 'CGV' or 'LGV'. This component can be used as any Dash component
  in Dash applications.
  - conf: JBrowseConfig obj
  - id: id for Dash components (opyional)
  - dash_comp: 'CGV' or 'LGV', defaults to 'LGV' when none is passed e.g
    `create_component`(cgv_with_conf.get_config(), dash_comp="CGV")
- `launch`(conf, \*\*kwargs) - launches a LinearGenomeView Dash component in a
  Jupyter cell
  - id: id for Dash components
  - dash_comp: 'CGV' or 'LGV', defaults to 'LGV' when none is passed
    > **Warning**: Only use `launch` in jupyter notebooks

### JBrowseConfig

Quick overview of the JBrowseConfig API

The JBrowseConfig API allows us to set an assembly, add tracks, set default
sessions, set custom color themes, and more.

JBrowseConfig().

- `set_assembly`(assembly_data, aliases, refname_aliases)
  - Sets the assembly subconfiguration
  - for the refname_alias subconfiguration check out the JBrowse
    [refname aliasing docs](https://jbrowse.org/jb2/docs/config_guide/#configuring-reference-name-aliasing)
- `add_df_track`(track_data, name, \*\*kwargs)

  - requires DataFrame to have columns ['refName', 'start', 'end', 'name']
  - refName and name columns must be strings, start and end must be int
  - if the score column is present, it will create a Quantitative track else it
    will create a Feature track.
  - not available for CGV
  - params:
    - df – pandas DataFrame with the track data.
    - name (str) – (optional) name for the track
    - overwrite (str) – (optional) flag whether or not to overwrite existing
      track.
    - track_id (str) - (optional) trackId for the track

- `add_track`(data, \*\*kwargs)
  - adds a track configuration given a file with track data
  - currently supporting cram, bam, vcf gzipped, gff/gff3 gzipped, bigbed,
    bigwig file types.
  - assumes an index exists within the same directory of the track data if no
    index url path is provided.
  - currently supporting Wiggle, Variant, Feature and Alignments tracks
  - params:
    - data (str) – track path or url
    - name (str) – (optional) name for the track
    - index (str) – (optional) index file for the track
    - track_type (str) – (optional) track type. If none is passed, the api will
      infer one based on the file type
    - overwrite (boolean) – (optional) overwrites existing track if it exists in
      list of tracks (default False)
- `delete_track`(track_id)
  - params:
    - track_id (str) - trackId for the track to delete
- `set_location`(location)
  - initial location for when the browser first loads, syntax
    'refName:start-end'
  - e.g 'chrom1:500-1000'
  - not available for CGV
- `set_default_session`(tracks_ids, display_assembly=True)
  - sets the default session given a list of track ids
  - params:
    - tracks_ids - list[str] list of track ids to display
    - display_assembly (boolean) – display the assembly reference sequence
      track. default=True
- `set_theme`(primary, secondary=None, tertiary=None, quaternary=None)
  - sets the theme in the configuration given up to 4 hexadecimal colors
- `set_env`(notebook_host, notebook_port):
  - Changes the port and the host for creating links to files found within the
    file tree of jupyter.
  - The port and host should match those configured in your jupyter config.
- `add_text_search_adapter`(ix, ixx, meta, adapter_id=None)
  - adds a trix text search adapter
  - not available for CGV
- `get_config`() - returns the configuration object
<!-- These configurations can be used to create [Dash JBrowse's Linear Genome View](https://github.com/GMOD/dash_jbrowse) components which can be used in any python application and or jupyter notebook. -->

<!-- The JBrowseConfig API allows us to set an assembly, add tracks, set default sessions, set custom color themes, and more. -->
 <!-- For full details please reference the documentation. -->

![Circular Genome View Gif](https://user-images.githubusercontent.com/45598764/152484043-aeff48b5-a1f2-44f2-b7d9-131c2afd4e1a.gif)

## Local file support

We currently support two ways of passing your local data to JBrowse Views.

For our **Jupyter lab and Jupyter notebook** users, you can create urls by
leveraging the Jupyter server where your notebook is running or you can provide
paths relative to root of the file tree. You can also provide paths relative to
the root of the Jupyter file tree. Examples of these can be found below or in
the local_support.ipynb.

For those using **colab notebooks and binder** (will also work in Jupyter) you
can use the JBrowse dev server. An example of how to use the JBrowse dev server
can be found below.

> **Note**: These solutions are recommended for your development environments
> and not supported in production.

### Jupyter Server

Jupyter Lab and Jupyter Notebook users can leverage the Jupyter server to create
urls or paths to pass to JBrowse Jupyter view configs.

Once you have the data within the file tree where the notebook is running, then
you will be able to format the urls or paths to pass to the API. (Note: you will
need to serve your entire project where the notebook is running.)

To verify that your data is in the correct place, you can navigate to
_http://your-host:your-port/tree_ . Make sure that you use the same port and
host that is used in your jupyter configuration.

e.g http://localhost:8888/tree is the url your should navigate to if you are
running your jupyter notebook in localhost in port 8888

If you have a different port or host, you can change the port and host used by
JBrowse with the use of the set_env(notebook_host, notebook_port).

Example: config = create("LGV) config.set_env("host", 9999).

#### Using Jupyter URLS

In this example, the notebook is configured to run in localhost in port 8888. It
is assumed that you have Jupyter lab installed in your venv.

File tree of the project:

```
- example_dir/
    - example.ipynb
    - data1.gff.gz
    - data2.gff.gz.tbi
```

Running Jupyter

```
(venv)$ cd example_dir
(venv)$ jupyter lab
```

This will be the url that you should see at the top of your browser if you
opened the example.ipynb http://localhost:8888/lab/tree/example.ipynb

Urls for file `data1.gff.gz` and `data2.gff.gz.tbi` would be in the form
`http://localhost:8888/files/<your_file_name>`.

- `http://localhost:8888/files/data1.gff.gz`
- `http://localhost:8888/files/data2.gff.gz.tbi` Note that you do not need to
  add lab or tree to this url.

You can use these urls. For example, you could add a track with these urls like
this:

```python

config.add_track(
    "http://localhost:8888/files/data1.gff.gz", # track data
    index="http://localhost:8888/files/data2.gff.gz.tbi", # track index
    track_id="example-track", # track id
    name="track-name" # track name
)
```

Resources:

- [Configuring the Jupyter Notebook server](https://jupyter-notebook.readthedocs.io/en/stable/config_overview.html#notebook-server)
- [Getting started with Jupyter Lab](https://jupyterlab.readthedocs.io/en/stable/getting_started/starting.html)

#### Using Jupyter paths

JBrowse also supports paths to files are within the Jupyter file tree (this only
works if you are running your notebook in Jupyter lab or Jupyter notebook).

You can repeat the steps in the previous section to ensure that your files are
in the correct place. Instead of formatting the urls yourself, you can pass
paths **relative to the root of the Jupyter file tree** .

Using the same structure of the previous example...

File tree of the project:

```
- example_dir/
    - example.ipynb
    - data1.gff.gz
    - data2.gff.gz.tbi
```

Running Jupyter

```
(venv)$ cd example_dir
(venv)$ jupyter lab
```

A user could then specify paths to data1 and data2 like this

```python

config.add_track(
    "/data1.gff.gz", # track data
    index="/data2.gff.gz.tbi", # track index
    track_id="example-track", # track id
    name="track-name" # track name
)
```

### JBrowse dev server

We also provide a simple http server configured with CORS that will allow you to
serve your local files from a specified directory within your machine.

> **Note** The use of local files or the dev server provided is not recommended
> for production environments.

You can spin the dev server in two ways.

1. Git clone this repo
2. From the root of this repository, you will be able to run the python file
   named `serve.py` `$ python serve.py`
3. You can choose your own port, host, and directory from which to serve your
   files. You can also press enter to choose all the defaults.

- Default PORT: 8080
- Default host: localhost
- Default directory: the current working directory -> os.getcwd() is used

4. Now that the dev server is running you can use the url provided in the
   terminal to pass to your views.

- For example: the url to the data you wish to pass to the JBrowse view config
  for the local dev server running on port 8080 on local host will look like
  this "http://localhost:8080/<your-file-name>" e.g
  `jbrowse_conf.add_track("http://localhost:8080/<your-file-name>", name="test-demo")`

Or you can make your own python file and run it to start the server.

1. create a python file named dev_server.py and add the code below

```
import os
from jbrowse_jupyter import serve


if __name__ == "__main__":
    serve(os.getcwd(), port=8080, host='localhost')
```

2. Run the python file `$ python dev_server.py`

3. This will spin up a python simple http server with cors enabled. You can take
   a look at our implementation of our dev server here:
   `jbrowse_jupyter/dev_server.py`

4. Now that the dev server is running you can use the url provided in the
   terminal to pass to your views.

- For example: the url to the data you wish to pass to the JBrowse view config
  for the local dev server running on port 8080 on local host will look like
  this "http://localhost:8080/<your-file-name>" e.g
  `jbrowse_conf.add_track("http://localhost:8080/<your-file-name>", name="test-demo")`

## JBrowse Jupyter vs Other tools

| Features                                            | JBrowse/ JBrowse Jupyter | IGV.js /igv-notebook | ipyIgv                | Gosling/Gos           | D3GB                  | PygBrowse          | Mango                 |
| --------------------------------------------------- | ------------------------ | -------------------- | --------------------- | --------------------- | --------------------- | ------------------ | --------------------- |
| Binder support                                      | :heavy_check_mark:       | :heavy_check_mark:   | :heavy_check_mark:    | :heavy_check_mark:    | :x:                   | :x:                | :x:                   |
| Colab support                                       | :heavy_check_mark:       | :heavy_check_mark:   | :x:                   | :heavy_check_mark:    | :x:                   | :x:                | :x:                   |
| Custom Color Theming                                | :heavy_check_mark:       | :x:                  | :x:                   | :heavy_check_mark:    | :x:                   | :x:                | :x:                   |
| Deletion of tracks                                  | :heavy_check_mark:       | :x:                  | :heavy_check_mark:    | :x:                   | :x:                   | :x:                | :x:                   |
| Export view as SVG                                  | :heavy_check_mark: \*    | :heavy_check_mark:   | :heavy_check_mark:    | :x:                   | :x:                   | :x:                | :heavy_check_mark:    |
| Local file support                                  | :heavy_check_mark: \*\*  | :heavy_check_mark:   | :heavy_check_mark:    | :heavy_check_mark:    | :heavy_check_mark:    | :heavy_check_mark: | :heavy_check_mark:    |
| Supports Circular Genome View                       | :heavy_check_mark:       | :x:                  | :x:                   | :heavy_check_mark:    | :x:                   | :x:                | :x:                   |
| Ability to enable text searching from indexed files | :heavy_check_mark:       | :x:                  | :x:                   | :x:                   | :x:                   | :x:                | :x:                   |
| Ability to add tracks from Dataframes               | :heavy_check_mark:       | :x:                  | :x:                   | :x:                   | :x:                   | :heavy_check_mark: | :x:                   |
| Zooming in on regions of interest                   | :heavy_check_mark: \*    | :heavy_check_mark:   | :heavy_check_mark: \* | :heavy_check_mark: \* | :heavy_check_mark: \* | :x:                | :heavy_check_mark: \* |

\* Feature is accessible via the component's UI and not by API. \*\* Path
support for local files is only available when running notebook in Jupyter lab
and Jupyter notebook. Local file support in colab and binder is available by
running the JBrowse dev server to host your data and creating urls to pass to
the JBrowse view. More information available in the
[local file support section of this readme](#Local-file-support)

- For more features of the JBrowse and JBrowse embedded components checkout
  [our documentation](https://jbrowse.org/jb2/docs/embedded_components/)
- Igv.js [documentation](https://github.com/igvteam/igv.js/wiki/)
- igv-notebook [documentation](https://github.com/igvteam/igv-notebook)
- ipyIgv [documentation](https://github.com/QuantStack/ipyigv)
- D3GB [documentation](http://d3gb.usal.es/index.html)
- PygBrowse [documentation](https://github.com/phageghost/python-genome-browser)
- Gosling [documentation](https://github.com/gosling-lang/gosling.js)
- Gos [documentation](https://gosling-lang.github.io/gos/)
- Mango
  [documentation](https://bdg-mango.readthedocs.io/en/latest/jupyterWidgets/usage.html)

## Resources

- [JBrowse](https://jbrowse.org/jb2/) - the next generation genome browser
- [JBrowse React Linear Genome View](https://www.npmjs.com/package/@jbrowse/react-linear-genome-view) -
  interactive genome browser
- [JBrowse React Linear Genome View Docs](https://jbrowse.org/storybook/lgv/main/?path=/story/getting-started--page) -
  storybook docs of React LGV
- [Dash Applications](https://dash.plotly.com/layout) how to get started to
  custumize Dash applications.
- [Dash HTML components](https://dash.plotly.com/dash-html-components) Dash html
  components to build the Dash application layout.
- [Dash Jupyter](https://github.com/plotly/jupyter-dash) library to enable
  embedding Dash components in jupyter notebooks.
- [Dash Jbrowse](https://github.com/GMOD/dash_jbrowse) suite of Dash components
  for JBrowse views. (JBrowse Linear Genome View)

## Contributing

See our [contributing guide](./CONTRIBUTING.md).

## Academic Use

This package was written with funding from the [NHGRI](https://genome.gov/) as
part of the JBrowse project. If you use it in an academic project that you
publish, please cite the most recent JBrowse paper, which will be linked from
[jbrowse.org](https://jbrowse.org/).

## Contact us

We **really** love talking to our users. Please reach out with any thoughts you
have on what we are building!

- Report a bug or request a feature at
  https://github.com/GMOD/jbrowse-jupyter/issues
- Join our developers chat at https://gitter.im/GMOD/jbrowse2
- Send an email to our mailing list at `gmod-ajax@lists.sourceforge.net`

## FAQ

### What file types are supported?

We currently support:

- bam
- bigwig
- bigbed
- cram
- indexed fasta
- bgzip indexed fasta
- gff3 tabix
- twobit
- vcf
- vcf tabix

### What track types are supported?

We currently support:

- [AlignmentsTrack](https://jbrowse.org/jb2/docs/user_guide/#alignments-tracks)
- [QuantitativeTrack](https://jbrowse.org/jb2/docs/user_guide/#bigwig-tracks)
- [VariantTrack](https://jbrowse.org/jb2/docs/user_guide/#variant-tracks)
- [ReferenceSequenceTrack](https://jbrowse.org/jb2/docs/user_guide/#sequence-track)
- Feature Tracks

For the circular genome view (CGV), we only support variant tracks. Check out
[track types](https://jbrowse.org/jb2/docs/user_guide/#sequence-track) docs for
more information.

### What views do you currently support?

We currently support JBrowse's Linear Genome View and Circular Genome View. We
hope to support more in the future.

### How do I configure text searching?

In order to configure text searching in your Linear Genome View, you must first
create a text index. Follow the steps found
[here](https://jbrowse.org/jb2/docs/quickstart_cli/#indexing-feature-names-for-searching).
Then you must create and add a text search adapter to your config.

### How do I configure tracks to show up on first render?

You can set a specific track/tracks to show up when the component first renders,
and you can do this via the default session. You can set the default session via
the JBrowseConfig API. `set_default_session`

### How do I set a custom color theme palette to fit with my application?

You can customize the color palette of the component through the use of
`set_theme` function from the JBrowseConfig API. Below is an image of an LGV
with a custom color palette.
![Custom Palette](https://github.com/GMOD/jbrowse-jupyter/raw/main/images/custom_palette.png)

### Can I use local files/my own data?

Yes, there are a couple of ways in which you can configure and use your own data
from your local environment in jbrowse views. 1. Make use of the jupyter
notebook/lab server. Intended for those running their notebooks with jupyter lab
or jupyter notebook. 2. Launch your own http server with CORS which will enable
you to use local files. You can run our serve.py to launch our dev server.
(Checkout our local_support.ipynb for tutorials on how to use your own data)

> **Note**: These solutions are recommended for your development environments
> and not supported in production.

### I am running a colab notebook/binder notebook and wish to use my local data, how can I do this?

You can run JBrowse dev server to serve local files to use in your JBrowse
views. More information on the dev server can be found in the local file support
section of this readme.

### My paths are not working?

If you are using paths, make sure you are in a jupyter environment (Jupyter lab
or jupyter notebook). Additionally, make sure that the port and host match the
ones in your config. If they are different, use the set_env(notebook_host,
notebook_port) to change the default port and host used by JBrowse to configure
paths in jupyter.

### My data says it's is loading and never loads?

If your view shows that it is loading and never loads, it could be a fetch error
or CORS. - the JBrowse Dev Server has CORS enabled.

- Make sure that your alias is correctly configured. Data that never loads could
  also indicate that the format is correct, but will not display anything for it
  if the assembly does not match.
- Data that never loads could also indicate that the port and host do not match
  where your data is hosted when using paths in jupyter envs
