Negligible Psychological Misery

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    0.7.2 • Public • Published


    Extension status Github Actions Status Binder PyPI version Conda version

    A JupyterLab extension highlighting misspelled words in markdown cells within notebooks and in the text files.

    The JupyterLab extension is based on the spellchecker Jupyter Notebook extension and relies on Typo.js for the actual spell checking. Spellchecker suggestions are available from the context menu. The style of the highlights can be customized in the Advanced Settings Editor.

    The extension provides (Hunspell) SCOWL dictionaries for:

    • American, British, Canadian, and Australian English
    • French,
    • German (Germany, Austria, Switzerland)
    • Portuguese,
    • Spanish

    and will also use the Hunspell dictionaries installed in known paths which vary by operating systems. If you use JupyterLab in a browser running on a different computer than the jupyter server, please note that the dictionaries need to be installed on the server machine.

    You can add custom dictionary by placing Hunspell files it in dictionaries folder in one of the data locations as returned by:

    jupyter --paths

    You should place two files with extensions .aff and .dic, and name following BCP 47 standards. For more details, please see the example below.

    JupyterLab Version

    The extension has been tested up to JupyterLab version 3.0.


    For JupyterLab 3.x:

    pip install jupyterlab-spellchecker


    conda install -c conda-forge jupyterlab-spellchecker

    For JupyterLab 2.x:

    jupyter labextension install @ijmbarr/jupyterlab_spellchecker

    Adding dictionaries - example

    If jupyter --paths looks like:


    and you want to add Polish language, you would put pl_PL.aff and pl_PL.dic in /home/your_name/.local/share/jupyter/dictionaries (you will need to create this folder), so that the final structure looks similar to:

    ├── dictionaries
    │   ├── pl_PL.aff
    │   └── pl_PL.dic
    ├── kernels
    │   └── julia-1.5
    │       ├── kernel.json
    │       ├── logo-32x32.png
    │       └── logo-64x64.png
    ├── nbconvert
    │   └── templates
    │       ├── html
    │       └── latex
    ├── nbsignatures.db
    ├── notebook_secret
    └── runtime

    Where to get the dictionaries from?

    Some good sources of dictionaries include:

    Using online dictionaries

    An alternative to saving the dictionary on your own disk (or more accurately on the disk where jupyter-server is set up) is fetching the dictionaries from a remote URL. This requires an Internet connection to load the dictionary (each time when you open JupyterLab or change the dictionary), and might be useful if you are not able to save dictionaries on disk (e.g. when using JupyterLab on JupyterHub configured by someone else).

    To configure the online dictionaries go to Advanced Settings EditorSpellchecker and set onlineDictionaries to an array of JSON objects like in the example below:

            "id": "en_US-online",
            "aff": "",
            "dic": "",
            "name": "My favorite variant of English"


    Development install

    Note: You will need NodeJS to build the extension package.

    The jlpm command is JupyterLab's pinned version of yarn that is installed with JupyterLab. You may use yarn or npm in lieu of jlpm below.

    # Clone the repo to your local environment
    # Change directory to the jupyterlab_spellchecker directory
    # Install package in development mode
    pip install -e .
    # Link your development version of the extension with JupyterLab
    jupyter labextension develop . --overwrite
    # Rebuild extension Typescript source after making changes
    jlpm run build
    pip install pytest

    You can watch the source directory and run JupyterLab at the same time in different terminals to watch for changes in the extension's source and automatically rebuild the extension.

    # Watch the source directory in one terminal, automatically rebuilding when needed
    jlpm run watch
    # Run JupyterLab in another terminal
    jupyter lab

    Before commit

    Make sure that eslint passes:

    jlpm run eslint:check

    If there are any issues it might be possible to autofix them with:

    jlpm run eslint

    Run tests:

    python -m pytest


    npm i @ijmbarr/jupyterlab_spellchecker

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