Copyright headers

This library has no copyright header. A project that needs one keeps its text in one file, and a tool writes it at the top of every file, as the comment of the file's language. The tool is license-check-and-add: add inserts the header where it is missing, check lists the files without it (and fails), remove removes it everywhere.

Set-up

pnpm add -D license-check-and-add

The text, without any comment syntax, in COPYRIGHT_HEADER.txt. ##…## marks a pattern, so any year matches when checking:

Copyright (c) ##[0-9]{4}## Company name. All rights reserved.

license-config.json: the comment of each file type.

{
  "license": "COPYRIGHT_HEADER.txt",
  "regexIdentifier": "##",
  "trailingWhitespace": "TRIM",
  "ignoreFile": ".gitignore",
  "ignore": ["**/*.json", "**/*.md", "**/*.yml", "**/*.yaml", "**/*.txt", "pnpm-lock.yaml", "**/.*"],
  "licenseFormats": {
    "ts|mts|js|mjs|scss|css": {
      "prepend": "/*",
      "append": " */",
      "eachLine": { "prepend": " * " }
    },
    "html|svg": {
      "prepend": "<!--",
      "append": "-->",
      "eachLine": { "prepend": "  " }
    }
  }
}

JSON has no comments, and the Markdown and YAML files are documentation and configuration: they are ignored.

Scripts in package.json (-r gives the year written by add):

{
  "scripts": {
    "copyright:add": "license-check-and-add add -f license-config.json -r $(date +%Y)",
    "copyright:check": "license-check-and-add check -f license-config.json"
  }
}

When it runs

• Before each commit, so nobody has to think about it: a pre-commit hook runs pnpm copyright:add and adds the files it changed. With simple-git-hooks:

  {
    "simple-git-hooks": {
      "pre-commit": "pnpm copyright:add && git add -u"
    }
  }

  then pnpm simple-git-hooks once to install the hook.

• In the CI, which catches a commit made without the hook (--no-verify, another machine): add pnpm copyright:check to pnpm check.

• At save, for TypeScript only: sonarjs/file-header (SonarQube S1451) reports a missing header, and eslint-plugin-headers writes it with --fix, so on save when the editor applies ESLint fixes. No lint rule covers HTML and SCSS: the hook is the reliable way.

Notes

• The header is a plain block comment (/*, not /**): JSDoc does not read it as the documentation of the first export, and Prettier keeps it as is.
• license-check-and-add has not changed since 2022; it is small and has no framework dependency. addlicense (Google, a Go binary) does the same with -f for the text file and -check for the CI, but must be installed on every machine.