Extension Error (exception: 'sources')

Hi,
I'm trying to build Typescript documentation, but I'm getting this error when executing make html SPHINXOPTS=-v (local paths replaced with $env_path for privacy):

Traceback (most recent call last):
  File "$env_path/lib/python3.8/site-packages/sphinx/events.py", line 110, in emit
    results.append(listener.handler(self.app, *args))
  File "$env_path/lib/python3.8/site-packages/sphinx_js/__init__.py", line 60, in analyze
    app._sphinxjs_analyzer = analyzer.from_disk(abs_source_paths,
  File "$env_path/lib/python3.8/site-packages/sphinx_js/typedoc.py", line 40, in from_disk
    return cls(json, base_dir)
  File "$env_path/lib/python3.8/site-packages/sphinx_js/typedoc.py", line 29, in __init__
    ir_objects = self._convert_all_nodes(json)
  File "$env_path/lib/python3.8/site-packages/sphinx_js/typedoc.py", line 113, in _convert_all_nodes
    converted, more_todo = self._convert_node(todo.pop())
  File "$env_path//lib/python3.8/site-packages/sphinx_js/typedoc.py", line 154, in _convert_node
    constructor, members = self._constructor_and_members(node)
  File "$env_path/lib/python3.8/site-packages/sphinx_js/typedoc.py", line 100, in _constructor_and_members
    ir, _ = self._convert_node(child)
  File "$env_path/lib/python3.8/site-packages/sphinx_js/typedoc.py", line 190, in _convert_node
    first_sig['sources'] = node['sources']
KeyError: 'sources'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "$env_path/lib/python3.8/site-packages/sphinx/cmd/build.py", line 276, in build_main
    app = Sphinx(args.sourcedir, args.confdir, args.outputdir,
  File "$env_path/lib/python3.8/site-packages/sphinx/application.py", line 278, in __init__
    self._init_builder()
  File "$env_path/lib/python3.8/site-packages/sphinx/application.py", line 337, in _init_builder
    self.events.emit('builder-inited')
  File "$env_path/lib/python3.8/site-packages/sphinx/events.py", line 117, in emit
    raise ExtensionError(__("Handler %r for event %r threw an exception") %
sphinx.errors.ExtensionError: Handler <function analyze at 0x7f0ca88759d0> for event 'builder-inited' threw an exception (exception: 'sources')

Extension error:
Handler <function analyze at 0x7f0ca88759d0> for event 'builder-inited' threw an exception (exception: 'sources')

Versions:
TypeDoc 0.20.14
Using TypeScript 4.1.3 from /usr/lib/node_modules/typescript/lib
Sphinx 3.4.3
Sphinx-js 3.1

I tried debugging, but I'm new to typedoc, so I'm kind of stuck.
What I could tell was that it crashes when processing the constructor of my class, in typedoc.py kind == Constructor

Any idea where this is coming from?

Reproduce the failure with make html SPHINXOPTS=-v using the reported TypeDoc, TypeScript, Sphinx, and sphinx-js versions. Start in typedoc.py at _convert_node, especially the kind == Constructor path and the access to node['sources']; done means the documentation build no longer raises the sources KeyError.