Leverage terser to mangle/compress the generated js messages

[minggangw]

This patch implements to leverage terser to mangle/compress the generated .js messages when --debug option not added. If debugging the message files, users can run generate-messages:dev to check with the original files, including:

1. Removing the prettier dependency.
2. Integrating terser minification with error handling for JavaScript files.
3. Using a conditional debug flag (isDebug) to determine whether to minify the code.
4. Don't remove the blank line in the generated files because it will be handled by terser now.

Fix: #1085

[Copilot]

Pull Request Overview

This PR updates the JS generation process to leverage terser for compressing and mangling the generated JavaScript messages instead of using prettier.

• Replaces the dependency on prettier with terser for production builds.
• Introduces a conditional minification step based on the isDebug flag.

[Copilot]

Consider adding error handling or logging around the terser.minify call to ensure that any minification errors are caught and handled, rather than silently falling back to the unminified code.

Suggested change

	result = await minify(code);
	try {
	result = await minify(code);
	} catch (error) {
	console.error(`Error minifying ${fileName}:`, error);
	result = null;
	}

[coveralls]

coverage: 85.355% (+0.04%) from 85.32%
when pulling 2cf0713 on minggangw:fix-1085
into a725c65 on RobotWebTools:develop.

[Copilot]

Pull Request Overview

This PR updates the code generation process to leverage terser for minifying generated JS code rather than formatting it with prettier. Key changes include:

• Removing the prettier dependency.
• Integrating terser minification with error handling for JavaScript files.
• Using a conditional debug flag (isDebug) to determine whether to minify the code.

Comments suppressed due to low confidence (2)

rosidl_gen/idl_generator.js:45

• Ensure that 'isDebug' is defined in the current scope or imported appropriately to avoid potential runtime errors during minification.

if (!isDebug && fileName.endsWith('.js')) {

rosidl_gen/idl_generator.js:55

• [nitpick] Consider assigning the minified code to the original 'code' variable before writing the file to improve clarity and maintainability.

await fse.writeFile(path.join(dir, fileName), result ? result.code : code);

[Copilot]

Pull Request Overview

This PR leverages terser to mangle and compress the generated JavaScript message files in place of prettier-based formatting. Key changes include:

• Replacing the prettier formatter with terser for minification.
• Removing the removeEmptyLines helper function and its invocations.
• Updating writeGeneratedCode to conditionally minify code when not in debug mode.