How to use black in `jupyter` notebooks

black_in_jupyter.md

1. Install the GUI extensions module

2. Go to the Nbextensions tab in your jupyter notebook

3. Tick code prettify

4. Paste the following in the json folding to enable black instead of whatever it’s set to:

{
  "python": {
    "library": "import json\ndef black_reformat(cell_text):\n    import black\n    import re\n    cell_text = re.sub('^%', '#%#', cell_text, flags=re.M)\n    try:\n        reformated_text = black.format_str(cell_text, 88)\n    except TypeError:\n        reformated_text = black.format_str(cell_text, mode=black.FileMode(line_length=88))\n    return re.sub('^#%#', '%', reformated_text, flags=re.M)",
    "prefix": "print(json.dumps(black_reformat(u",
    "postfix": ")))"
  },
  "r": {
    "library": "library(formatR)\nlibrary(jsonlite)",
    "prefix": "cat(toJSON(paste(tidy_source(text=",
    "postfix": ", output=FALSE)[['text.tidy']], collapse='\n')))"
  },
  "javascript": {
    "library": "jsbeautify = require('js-beautify')",
    "prefix": "console.log(JSON.stringify(jsbeautify.js_beautify(",
    "postfix": ")));"
  }