feat(cli): add lb4 copyright command to generate/update file headers

[raymondfeng]

Add lb4 copyright command to update JS/TS file headers with copyright and license. Ported from strong-tools with enhancement to support lerna managed monorepo.

Todos:

• Add tests
• Add docs

Checklist

👉 Read and sign the CLA (Contributor License Agreement) 👈

• npm test passes on your machine
• New tests added or existing tests modified to cover all changes
• Code conforms with the style guide
• API Documentation in code was updated
• Documentation in /docs/site was updated
• Affected artifact templates in packages/cli were updated
• Affected example projects in examples/* were updated

👉 Check out how to submit a PR 👈

[bajtos]

Great idea 👍

Since this new command is a part of the public package @loopback/cli, we need to write some documentation.

• As a LB user dealing with copyright headers, how am I going to discover that LB4 CLI provides a tool for my situation?
• As a LB user not using copyright headers yet, when I discover a new copyright command in CLI help, where can I learn more about this command and whether (or when) to use it in my project?
• As a LB user interested in using this new command, how can I learn about the configuration options - how to set the copyright owner, etc.

[bajtos]

Have you considered using ES6 template literals instead of lodash templates?

function license({license, ref}) {
  return [
    `This file is licensed under the ${license}.`,
    `License text available ${ref}`,
  ];
}

[raymondfeng]

It's a bit involved. We can defer it for future improvement.

[dhmlau]

+1 on having docs on the usage. Other than that, LGTM. Thanks @raymondfeng !

[dhmlau]

I have a question about the default owner value.
Please also update https://github.com/strongloop/loopback-next/blob/master/docs/site/Command-line-interface.md to include the command as well.

Other than that, LGTM. No need further reviews from me. Thanks.

[raymondfeng]

Updated docs/site/tables/lb4-project-commands.html

[achrinza]

It's probably out-of-scope, but we could create a future improvement PR to...

1. Leverage spdx-license-list

2. Utilize SPDX-License-Identifier

I'm wondering if it should be ported into the LoopBack CLI. A copyright header management tool may be better-suited as a separate package that can be depended upon and called from the LoopBack CLI. This would allow users to utilize the tool a-la carte without needing the entire LoopBack CLI.

[raymondfeng]

Leverage spdx-license-list
Utilize SPDX-License-Identifier

Thank you for the suggestion. I would like to integrate with the module but it will add at least 7MB to the dependency tree :-(.

I'm wondering if it should be ported into the LoopBack CLI. A copyright header management tool may be better-suited as a separate package that can be depended upon and called from the LoopBack CLI. This would allow users to utilize the tool a-la carte without needing the entire LoopBack CLI.

The utility is ported from https://www.npmjs.com/package/strong-tools and improved with lerna support. We can possibly break down cli module into a few packages in the future and introduce extensibility via @loopback/context.

[raymondfeng]

@achrinza I have improved the PR to use spdx list and https://www.npmjs.com/package/inquirer-autocomplete-prompt. But it seems to be causing test issues.