Fail to initialize searching index for languages other than 'en'

I checked that…

• … the documentation does not mention anything about my problem
• … the problem doesn’t occur with the default MkDocs template
• … the problem is not in any of my customizations (CSS, JS, template)
• … there are no open or closed issues that are related to my problem

Description

Version 5.5.1 and 5.5.2 fails to initialize search index with Japanese search mode but version 5.5.0 works well.

Expected behavior

5.5.0 works well.

git clone https://github.com/SI-Aizu/documentation.git
cd ./documentation
git checkout cd36072
docker-compose up

Open http://0.0.0.0:8888/, search with a Japanese word or an English word, it works well.

$ docker-compose run --rm --entrypoint=bash mkdocs
$ python --version
Python 3.8.5
$ mkdocs --version
mkdocs, version 1.1.2 from /usr/local/lib/python3.8/site-packages/mkdocs (Python 3.8)
$ pip show mkdocs-material | grep -E ^Version
Version: 5.5.0

Actual behavior

In 5.5.1 and 5.5.2, it shows only the message Initializing search and I cannot search with any word (any language). My browser console (Google Chrome) put the following error.

git clone https://github.com/SI-Aizu/documentation.git
cd ./documentation
git checkout a654e3b
docker-compose up

Uncaught TypeError: Cannot set property 'stemmerSupport' of undefined    index.ts:63
    at lunr.stemmer.support.min.js:1
    at lunr.stemmer.support.min.js:1
    at lunr.stemmer.support.min.js:1
    at index.ts:63
    at a (index.ts:85)
    at index.ts:109

$ docker-compose run --rm --entrypoint=bash mkdocs
$ python --version
Python 3.8.5
$ mkdocs --version
mkdocs, version 1.1.2 from /usr/local/lib/python3.8/site-packages/mkdocs (Python 3.8)
$ pip show mkdocs-material | grep -E ^Version
Version: 5.5.1

Steps to reproduce the bug

I already wrote about this above.

Package versions

I already wrote about this above.

Project configuration

I am using the same configuration between the 3 versions.

# Project information
site_name: 'SI-Aizu Documentation'
site_description: 'SI-Aizu Documentation'
site_author: 'SI-Aizu'
site_url: 'https://si-aizu.github.io/documentation'

# Copyright
copyright: '© 2020 SI-Aizu'

# Repository
repo_name: 'GitHub'
repo_url: 'https://github.com/SI-Aizu/documentation'
edit_uri: 'https://github.com/SI-Aizu/documentation/edit/main/docs'

# Configuration
docs_dir: 'docs'
theme:
  name: 'material'
  language: 'ja'
  shortcuts:
    help: 191    # ?
    next: 78     # n
    previous: 80 # p
    search: 83   # s
  palette:
    primary: indigo
    accent: orange
  # features:
  #   - tabs
  #font:
    #text: 'Ubuntu'
    #code: 'Ubuntu Mono'
  #icon:
    #logo: 'images/logo.svg'
  #favicon: 'assets/images/favicon.ico'

# Extensions
markdown_extensions:
  - admonition
  - codehilite
  - footnotes
  - mdx_math:
      enable_dollar_delimiter: true
  - toc:
      permalink: true
      separator: '_'

plugins:
  - search:
      separator: '[\s\-\.]+'
      lang:
        - ja

# Customization
extra_javascript:
  - 'https://cdnjs.cloudflare.com/ajax/libs/mathjax/2.7.6/MathJax.js?config=TeX-MML-AM_CHTML'
extra_css:
  - 'assets/css/custom.css'
extra:
  # manifest: 'manifest.json'
  social:
    - icon: 'fontawesome/brands/github-alt'
      link: 'https://github.com/SI-Aizu/documentation'

System information

• OS: macOS Mojave 10.14.6
• Browser:
  • Google Chrome Version 84.0.4147.105 (Official Build) (64-bit)
  • Microsoft Edge Version 84.0.522.52 (Official build) (64-bit)

[squidfunk]

Released as part of 5.5.3.

[ryo1988]

When I tried 5.0.0, it was not successful. I changed the “HKEY_CLASSES_ROOT.js\Content Type” in the registry from “text/plain” to “text/javascript” and it became OK. Do I have to set the “HKEY_CLASSES_ROOT.js\Content Type” in the registry to “text/javascript”?