print source-able pwsh completion script for Node.js

node-pwsh-completion.mjs

import { execFile as childProcessExecFile } from "node:child_process"
import { execPath, stdout } from "node:process"
import { promisify } from "node:util"

const execFile = promisify(childProcessExecFile)

const pwshCompletionTemplatePrefix =
`using namespace System.Management.Automation
using namespace System.Management.Automation.Language

$options = `

const pwshCompletionTemplateSuffix = `

Register-ArgumentCompleter -Native -CommandName 'node' -ScriptBlock {
    param($wordToComplete)

    if ($wordToComplete -like '-*') {
        $options | Where-Object {
            $_.StartsWith($wordToComplete)
        } | ForEach-Object {
            Write-Output -InputObject (New-Object -Type System.Management.Automation.CompletionResult -ArgumentList $_, $_, "ParameterValue", $_)
        }
    }
}`

// @see {@link https://github.com/nodejs/node/blob/v20.16.0/src/node_exit_code.h#L8}
const kNoFailure = 0

// @see {@link https://github.com/nodejs/node/blob/v20.16.0/src/node_options.cc#L1132-L1168}

const prefix =
	"_node_complete() {\n" +
	"  local cur_word options\n" +
	"  cur_word=\"${COMP_WORDS[COMP_CWORD]}\"\n" +
	"  if [[ \"${cur_word}\" == -* ]] ; then\n" +
	"    COMPREPLY=( $(compgen -W '"

const suffix =
	"' -- \"${cur_word}\") )\n" +
	"    return 0\n" +
	"  else\n" +
	"    COMPREPLY=( $(compgen -f \"${cur_word}\") )\n" +
	"    return 0\n" +
	"  fi\n" +
	"}\n" +
	"complete -o filenames -o nospace -o bashdefault " +
	"-F _node_complete node node_g" +
	// An additional LF is appended during `printf()`
	// @see {@link https://github.com/nodejs/node/blob/v20.16.0/src/node.cc#L1040}
	"\n"

const nodeProcessPromise = execFile(execPath, ['--completion-bash'], {
	encoding: 'utf8'
})
const { child: nodeProcess } = nodeProcessPromise
const { stdout: nodeOut } = await nodeProcessPromise

// EOL is dependent on the platform and we need to normalize it
const nodeBashCompletion = nodeOut.replace(/\r?\n|\r(?!\n)/g, '\n')

if (nodeProcess.exitCode !== kNoFailure || !nodeBashCompletion.startsWith(prefix) || !nodeBashCompletion.endsWith(suffix)) {
	throw new Error('Unsupported node bash complete output')
} else {
	const items = nodeBashCompletion.slice(prefix.length, -suffix.length).split(' ')

	stdout.write(
		pwshCompletionTemplatePrefix +
		items.map(item => `"${item}"`).join(', ') +
		pwshCompletionTemplateSuffix
	)
}